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/diy/ - Do-It-Yourself

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1901845 No.1901845 [Reply] [Original] [archived.moe]

Thread delaminated during repair:>>1896523

>I'm new to electronics. Where to get started?
It is an art/science of applying principles to requirements.
Find problem, learn principles, design and verify solution, build, test, post results, repeat.

>Project ideas:
Don't ask, roll:

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors
Horowitz and Hill, The Art of Electronics

>Design/verification tools:
NI Multisim
iCircuit for Macs
KiCAD (PCB layout software, v5+ recommended)

Mouser, Digi-Key, Arrow, Newark, LCSC (global)
RS Components (Europe)
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors

>Related YouTube channels:

>Li+/LiPo batteries
Read this first:http://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf

>I have junk, what do?
Shitcan it

>> No.1901854

Oh boy, a ceramigg gapacidor :DDDD

>> No.1901855
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i want to rebuild some old dewalt ni-cd 18v batteries with li-ion cells. to get the same voltage i will use a 5s configuration and will get the appropriate BMS. what i am not sure about is how do i charge this pack after i finish? can i use the old ni-cd 18v charger with only a positive an negative contact? why do dewalt and other brands li-ion systems have all those extra pins on the charger and battery? i thought a bms has a charge controller and balances your parallel groups so all you need to charge a custom pack is the right voltage charger.

>> No.1901864
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I get 25mW DC on the end
Do i need a resistive load

>> No.1901872

wrong unit.
>Do i need a resistive load
no. check your wiring and multimeter settings. then check if your fuse is open circuit, same for other parts like the transformer windings.

>> No.1901875

Reposting in new thread
Please send help

>> No.1901882
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Now I got 48V AC between the filters and ground
Which is interesting since the tranny is 2x15V in series

>> No.1901886

what tranny? the bridge rectifier? if you're this unfamiliar then you should post exactly where you're measuring with both probes in relation to your schematic.

>> No.1901888

oh sorry just realized you meant the transformer.

>> No.1901892
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>> No.1901895

it's not clear what your 48V measurement is *across*. you could plausibly get 48V DC across the outputs considering high line and bad tolerances and no load, but you should get little AC when measuring downstream of the bridge. i'm just worried you're measuring AC from the secondary ground to one of the primaries or some dumb shit.

>> No.1901900

>tranny is 2x15V in series
Is it (center) tapped or actually in series?
Center tapped isn't two transformers in series, it's one transformer with two outputs.
I'm pretty sure you mean it's a center tapped 230V to 30V / 2x15V.

The 230V is it's rated input, are you sure you're putting in 230V AC?

What's the volts across the transformer output before the diodes?

>> No.1901911


AC voltage is written as effective voltage...when you rectify the ac you rectify up to the PEAK voltage which you get by multiplying with sqrt(2)....30 *sqrt(2) is about 43 volts and you add come capacitor overhead and you get about that voltage

>> No.1901919
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i think you will need to stage your transistors differently ...you lose about 0.8 V on each jump which is basically the ammount on you Base emiter diode voltage ....the picture is a MOSFET driver circuit ffrom the TN90002 application note from nxp semiconductors

>> No.1901921
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I'm looking to replace my lost set of probe leads. . I've noticed that you can buy 10A and 20A for the same price.
what's the difference between them? why should I not go with 20A version? Any reason?

>> No.1901924

Thicker wires?
Can your multimeter even do 20A?

>> No.1901926

>Thicker wires?
That has to be the only difference even though they look identical in pictures I've seen (only the 10A/20A labeling on probes is different in pics).
>Can your multimeter even do 20A?
Well, they say this about it:
>10 A (20 A for 30 seconds maximum)
even though I've never even gone over 5A in my home lab.

>> No.1901928

The extra pins are connected between each set of cells in series so that the charger can balance each cell. One of the pins is also typically a temperature sensor which will tell the charger or tool to shut off if the battery gets too hot. You absolutely cannot use ni-cd chargers to charge lithium batteries. The most important thing to remember when charging lithium batteries is you must not exceed 4.2v per cell. A ni-cd charger might try to trickle charge the battery at the end of the charge cycle which would overcharge a lithium battery and could cause a fire.

>> No.1901930

also why did you use two 2.2k resistors instead of one ?

>> No.1901931
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can I get a consensus on laptops of /ohm/?
you're all using macs, right?

>> No.1901934

i don't have a laptop. i had three sitting around and tossed them because they really don't have a niche in between desktops and smartphones anymore.

>> No.1901936

No I'm not a gay web designer, I have a thinkpad

>> No.1901937

i generally use a desktop pc for everything becuase i use EDA, CAD , and sim software and would pluck out myhair one by one if i had to do all that on a laptop ...but i have fixed some lenovo notebook (isnt a thinkpad but i wish it wa) i got that was "broken" and use that if i need to travel or need to program something in the field

>> No.1901938

also fuck off to /g/ and their consoomer containment boards

>> No.1901942

>That has to be the only difference even though they look identical in pictures I've seen (only the 10A/20A labeling on probes is different in pics).
These are some generic Chinese ones, right?
Maybe they literally only changed the labelling and they will run hot at 20A.

>> No.1901946

>you're all using macs, right?
My work provided me with MBP.
t. poorfag.

>> No.1901948
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Yeah, the windings are connected.
Now how do I get the DC voltage that I have? I'm only getting a few mV DC measuring from the end of the circuit.

>> No.1901954

First of all check that you actually set your multimeter on DC voltage ...also try connecting an analog light bulb onto the ends or a resistor and then measure the voltage like that , some transformers show no output if you dont load it first (pull current)

>> No.1901973

Oh, you think it’s dropout? For some reason that idea never occurred to me. But it’s 5V away from each rail at the output, and 4V away from each rail in the intermediate stage. The problem appears to be rippling down from the first transistor, or at the very least the first transistor’s action is being interfered with by the later stages. Your pic is just a single-stage totem-pole, which might be ok, but I want the extra current of a Darlington.
I guess I’ll see about disconnecting the later stages from the first transistor to see if it’s not working by itself. Think a schottky transistor arrangement would be better?

Can’t find my 1ks. They’re 2k too, not 2k2, which is a little odd.

>> No.1901988

TS100 or T12?

>> No.1902012


TS100 if you suck your wife's BBC bull; T12 if you just watch.

>> No.1902015

What does an aryan chad use?

>> No.1902019
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>> No.1902032

t. poorfag
Nothing gets done on thinkpad, only fixing issues

>> No.1902035

kek that's what I use

>> No.1902036

OP here, get your fucking consumerism out of my thread.

>> No.1902038

>the chad $5 mains-referenced, non-adjustable 10W iron
>the virgin $2000 soldering and rework station

>> No.1902049

Thanks pal, how about a power supply? Are there any to avoid if I'm gonna get a low budget one from aliexpress... any I might want to consider?

>> No.1902050

Just buy absolutely nothing, don't use anything, live in the woods.

>> No.1902051

I always buy second hand

>> No.1902052
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>> No.1902058

vbe is nominally 0.7v, so under ideal conditions you can get within 1.4v of the rail. You can replace the darlingtons with sziklai pairs to reduce that to 0.7v. That's "in theory", in reality with big BJTs, vbe starts out at more than 0.7v and increases rapidly the more current you put through. To really get the full range you have to flip them around and drive the high and low transistors separately with inverted signals (be sure to leave some dead time)
Also you need to put some capacitance on your rails. It's not "for safety" like putting on a rubber, you actually have to do it before you can have any fun.

>> No.1902080
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you can get a variety of RDtech power supply front ends, some cheap. you provide a fixed power supply, and a case. like this (fucking spam filter): https://www.aliexpress.com/item/32685851250.html

personally, I prefer a simple home-made unit from junk parts.

>> No.1902089

If I have 8k sample rate music and doing raw samples i should have a low pass filter at 4K right.

>> No.1902090

On its output I mean

>> No.1902101

>sziklai pairs
Don’t they drive the final transistors via a pull-up resistor? I’m already pushing close to the 0.25W limit per resistor (or I would be if I had 1ks) so I’m trying to stick just to transistor-transistor topologies for the output stage, and I also care somewhat about quiescent current. Thing is, there’s only 1V of dropout from each stage in the Darlington, the rest is all coming from the initial inverter as far as I can tell. Gonna read the data sheets anyhow and hope I’m not doomed.
Big cap is a good idea that I can’t believe I forgot, though I couldn’t see my supply rails rippling at all, or at least not on the same order of magnitude of a 0.7V be drop.

A proper common-emitter driver with dead-time would be a real pain, but probably not impossible. I think a single Schmitt trigger and an RC filter would be sufficient for that dead time. Might need a little digital logic too though. This is just for a bodge board to solder in place of a dedicated MOSFET driver, so it can’t be too big.

>> No.1902102

So it’s a DAC? Yeah I guess so, though it’s not intrinsically necessary. It will probably sound better, but at 4k bandwidth it’s already gonna by pretty bad. For an ADC though it really is necessary, and you’d cram as many poles to that filter as you need to, else nyquist will give you aliasing issues.

>> No.1902106

>Don’t they drive the final transistors via a pull-up resistor
Oh no they just use it for turning off, which is fine for speed but still might be bad thermal-wise. Looks like a Sziklai pair totem pole needs some more biasing, but I’ll definitely consider it if it will solve my problem.

>> No.1902118

Okay yeah it’s phone quality. I am using an internal op amp so I won’t get the benefit of the filter before the op amp to reduce some noise that it can cause but I was hoping of getting rid of the sharp shit out from the op amp. Although I was thinking of having it run at a higher sample rate then averaging samples so the spikes won’t be an issue Atleast will be at higher frequencies farther up and away from human hearing range not sure if this is a good idea though. Id ideally run it at 32k or something if I can do the math fast enough haven’t done the throughput calculations though. Also easiest way would have these calculations be done in a interrupt when it is getting the samples off of a spi bus which would increase time in the interrupt. itd also make the interrupt to put samples on the dac faster further making collisions more likely and making consequences for collisions worst. (No DMA sadly and no priority interrupts) is this a stupid idea?

>> No.1902119

I am looking at the DPSxxxx range, thinking about the high end DPS5020 50V 20A one actually, but the computer connectivity thing... I'm not too interested in Windows, are there some active Linux projects that could be used?

>> No.1902127

I might actually build that power supply in your attachment, would I be right in thinking it would give quite high quality power, eg no overshoot, low ripple? What would be appropriate values for the capacitors?

>> No.1902156

>Linux projects
Look for what people are doing with raspberry pi computers, might be something relevant there. More low-level and less user friendly, but as a Linux boy that shouldn’t be too high a hurdle.
If that doesn’t show up anything, you may just be able to get any old MCU with direct USB and have it ID as the correct sort of peripheral, so long as it fits into the USB class. If that fails, you’re gonna have to write drivers.

>> No.1902161

Yeah it’s pretty good, but it’s missing the load resistor since LM317s act up a little if you don’t draw enough current. The minimum dropout and minimum output voltage could also be better, so I’d look into a more modern adjustable regulator. Only 2A or whatever too. Could also use an emitter follower or something similar to get a practically 0V minimum output voltage. Add an op-amp to each transistor in a negative feedback loop and you’ve got really good ripple rejection AND a low dropout AND a 0V minimum voltage.

For capacitor values you can calculate how much capacitance you need for a certain ripple voltage and current, it’s a relatively simple equation that you might be able to work out via dimensional analysis or geometry of the ripple wave (simplified to a sawtooth).

>> No.1902172

I made a metal melter thing out of a microwave oven transformer by replacing the secondary winding with two turns of 2 gauge wire.

It did successfully melt a 3/16" stainless steel bolt.

But this got me thinking, the resistance of the primary winding is only 0.25 ohm, and I'm plugging it into 120V, which by ohms law means it should draw 480 amps. Why doesn't the primary winding burn up or blow the circuit breaker?

>> No.1902179

Inductance, my friend. Also mutual inductance with the secondary. If you put 120VDC through the primary it definitely would become an arcing puddle of copper, but AC power feels an extra resistance (or more technically, a reactance) due to storing energy in their magnetic field (E = 1/2 * L* I^2).
For a single inductor, you can calculate this reactance (measured in ohms) by knowing V = L*dI/dt, where L is the inductance of the inductor.
It's been ages since I did mutual inductors though, so I couldn't tell you much about those.

Inductors are the opposite of capacitors, which are defined as I = C*dV/dt, where C is the capacitance of the capacitor. Capacitors also have a reactance due to storing energy in their electric field (E = 1/2 * C * V^2).

Also note that both these reactances are not resistances in the normal sense, since they don't obey V=IR. Do the calculations and graph current next to voltage for a selected capacitor if you're up to it, the result is somewhat interesting.

>> No.1902183
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I have some strange vibrations filling the whole house from basement to roof, and 4 acre of land around..
I put some piezzo-electric sensors to bust the problem, but cannot give a reality to its origin.
the closest neighbour is a bakery but claims it's not him.
Could a neighbourhood electric lines concentrator produce such a mess ?

>> No.1902186
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>> No.1902188

Noob here, what are useful things to do with an oscilloscope? So far I can imagine examining PWM waveforms, looking at rise times and patterns of power supplies... what else?

>> No.1902190

>since they don't obey V=IR.
They pretty much do, it's just not the DC version of that equation, with impedance instead of resistance. Reactance is 1/impedance.

I guess impedance is technically Z instead of R, but it's the same equation.

You clearly know/knew this if you know the equations and reactance. What happened, anon, did the ASIC man get you?

For those interested:

>> No.1902209
File: 225 KB, 1462x770, dual rail bipolar dual polarity regulated power supply using lm317 lm337 - output goes to zero.gif [View same] [iqdb] [saucenao] [google] [report]

>What would be appropriate values for the capacitors?

always the same rule of thumb: 1000uF per amp of expected output.

if you use this variation of the circuit (pic) then the output will go very close to zero volts instead of a min. of +1.25 and -1.25.

>> No.1902211

FFT it. Could just be noise triggering a resonance mode of your piezo.

Curve tracing in XY mode. Put a component like a diode or capacitor in series with a resistor, put an (isolated) AC source across them both, clip ground to the middle and put the X channel across the component, and the Y channel across the resistor, and invert it.

>They pretty much do
Yeah I guess, my point was more that there's more to it than just resistance and frequency, as reactance is frequency dependant too.
>Reactance is 1/impedance
Isn't that conductance = 1/ resistance? With susceptance and admittance too if you want to play that way.
Reactance just means the strictly imaginary part of impedance, while resistance is the strictly real part.

Not him, but I'm sticking to my op-amp circuit thanks.

>> No.1902212

Noob here, what is "Wire wrapping wire" for?

>> No.1902233

Wire wrapping. It’s a form of circuit building, where wires are wrapped tightly around pins. It’s like a clean and high-density form of classic point-to-point wiring. I think it was mainly used before PCBs were commonplace, though it’s also somewhat useful for being less permanent, and it doesn’t have a PCB’s layer limitation. Usually a wire-wrapping gun was used to make a good couple of solid twists of wire around the pin. I think the connection was made more secure because the gold-plating on the pin cold-welded somewhat to the tin plated wire.

Wire wrapping wire is still used for other uses, it just happens to be a rather useful gauge of solid-core hookup wire. I think it fits fine in breadboards.

>> No.1902234

>1000uF per amp of expected output
That’s at mains frequency, right?

I = C*dV/dt, dt = 1/(2f) with a full bridge
C = I/(2f*ΔV)
If I=1A, f=50Hz, then for C to equal 1E-3, ΔV must be 10V. Which is really shitty ripple voltage. Have I done something wrong here? Because 1mF sounds fine to my intuition.

>> No.1902235

Hey guys, know how you measure conductance? In siemens!
heh, semen

>> No.1902244
File: 18 KB, 459x332, 41YUQ3 A6bL._AC_SY400_.jpg [View same] [iqdb] [saucenao] [google] [report]

Planning on wiring one of these bilge blowers for a mini spray booth.
Want it to plug into the wall socket, and a PWM to control the speed.
Anything to look out for as a beginner? Protective circuitry and such?

>> No.1902253

those are generic chinese multimeter leads where they just stamp whatever on it ...they are not nescesarily bad , since they are pretty much good enough for any multimeter up to like 5 and a half digits but i wouldnt use them for a constant 20 amps because they would get nice and toasty

>> No.1902256

no sizlaki pair mean you have a cascade of npn and pnp pair with a pulldown resistor that turns it off ..thats why i said originally you need to stage the transistors differnetly ...but with that you will also get about 0.7 voltage drop (maybe a bit less if you serach for an efficient trans) because the nature of BJT transistors because you always need a biasing voltage (static bias voltage is the reason they are not very efficient for switching applications)...also what is it exactly that you are driving ? driving MOSFET gates does not usually need a lot of current unless you are doing very fast switching and need to discharge the gate forcefully which can also be done in a lot of different ways that circumvent the need of very high power gate drivers ....also its extremly useful and easy to use an IC MOSFET gate driver like the LM25101

>> No.1902257
File: 1.00 MB, 2222x1667, SAM_0979.jpg [View same] [iqdb] [saucenao] [google] [report]

I have this connector for my multimeter that connects to its thermocouple for temperature measurement... anyone know if you can buy that kind of connector, just the one that plugs into the multimeter plugs? For making some custom multimeter attachments

>> No.1902259 [DELETED] 
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This is it plugged into

>> No.1902260
File: 888 KB, 1667x2222, SAM_0986.jpg [View same] [iqdb] [saucenao] [google] [report]

This is it plugged in, the part with "K-TYPE" written on it

>> No.1902261
File: 120 KB, 600x564, apu.png [View same] [iqdb] [saucenao] [google] [report]

>make SMD reflow station from cheap toaster oven
>put caution stickers all over it
>write "LEAD CONTAMINATED DO NOT COOK WITH" on front glass in permanent marker
>roommate still cooks with it

>> No.1902263

Why not get some banana plugs and use those?

>> No.1902265

Just want them joined together, maybe I should glue some banana plugs onto a spacer

>> No.1902267


examining any waveform , looking at and decoding digital signals ,analyzing dynamics of filters and oscilators , analyzing the dynamics of electrical motors , analyzin the waveforms of different methods of DC , stepper and AC motor drivers, analyzing and plotting OP amplifiers bandwitdh , transistor bandwidth , looking at bias voltages for different classes of amplifiers ....basically anything you can think of that needs to look at how the signal acts in a given circuit

>> No.1902269
File: 15 KB, 500x405, dual banana plug.jpg [View same] [iqdb] [saucenao] [google] [report]


>> No.1902270


>> No.1902271

if you type into google thermocouple adapter "name of multimeter brand" it should list out if they are available to be bought or not ...if they are open one up and wire it up

>> No.1902272
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yw fren

>> No.1902280
File: 86 KB, 874x817, IMG_20200904_141046~2.jpg [View same] [iqdb] [saucenao] [google] [report]

Can I get around buying a new thermostat for my washing maschine? Can I repair it, or building something? Use another one, for some other use case? Having difficulties finding one for mine, and it costs at least like 15€. Even, why? What's so expensive? Its a ELTH 262 K-11 T130.

>> No.1902281
File: 159 KB, 680x656, large-C.png [View same] [iqdb] [saucenao] [google] [report]

Linear discharge approximation
Vpp=ripple voltage
If I = 1A, 2f = 100Hz and Vpp = 1V
then C = 1e-2 F = 10e-3 F = 10mF

There's a nice calculator at
You can play with the values; scroll down and read the caveat.
Example: use as is but change C to 10000µF.

>> No.1902284

I have a hex dump of a flash chip that I know is good so I'm using it to write to bricked devices and it fixes them.
However, the serial number is stored in the dump and I'd like to be able to change it to match the device I'm flashing it to.
I've found the serial number in the dump, it's stored as four bytes.
The first two bytes are mapped directly to the serial number (ie. if bytes are F2 0D then the serial begins with F20D)
The last 2 bytes are giving me trouble as there seems to be something weird going on.

The serials can either have 8 or 9 characters and the last nibble of the last byte also seems to map directly (if the entire serial is stored as F2 0D XX XF, the serial will be F20DXXXF or F20DXXXXF).

So at the start I found changing the last two bytes to 9A E3 gave me 84303.
So I tried 00 00 and it maps straight to 0000
Now I've tried 12 34 and it mapped to 02914
which looks like the four maps directly over and the 123 is just 291 stored in hex.
But this doesn't make sense for the earlier ones like how does 8430 fit into 3 nibbles?

>> No.1902287

you might be if you can search by serial number ...but most of the service parts are bought from vendors because servic man fees andshit ....they should be basic bimetal thermostast like they use in cars...its basically a plunger with a spring that contracts once it gets to a set temperature ...basically if you find another thermostat with the same temperature rating and it fits into your enclosure it should work

>> No.1902297

so if those oem batteries have balancing pins does that bean they dont have a bms in the pack and require a smart- li-ion charger?
if my custom pack has a bms doesnt that prevent overcharging even with a dumb charger?

>> No.1902306

Half the time you say the serial number is a hex value. The other times you say the serial number is a decimal value. Or maybe you're saying that some of the time PART of the serial number is decimal. Stick with one or the other and maybe you will understand the issue.

>> No.1902309

Okay,for instance

Serial number 708C4195C is stord as 70 8C 4C 3C
so the 70 8C is part of the serial is just the actual hex data.
Also the C at the end is just the C from hex but somehow the 4195 is stored as 4C 3.

I just realised I can read the the serial number from the chip of the bricked units and then write it back but I've one unit that I already flashed before reading the serial.

I know the serial should be 70A684967
so it should be stored as 70 A6 XX X7.
I'm just not sure what the XX X should be

>> No.1902313

C3 hex is 195 in dec

>> No.1902314

Yeah just seen that.
But the serial I want needs 8496 stored as XXX and it can't just be 8 XX as 496 is 3 hex digits

>> No.1902316

Okay serial ending in 84303 was stored as 9A E3
so I'm thinking 8XX3
430 is 1AE in hex to the one carries on to the 8 and becomes 9AE3.

I'm gonna attempt storing 89467 as 9F 07 and see if it works

>> No.1902323

Okay thanks, I'll ask in a shop for car parts as well. The people in my hardware store looked at me like I would try to give them cancer, when asking them for it.
Somewhere on the net I found that the price is more like 3$ from the supplier, so the extra I saw on other pages for similar ones is probably bc it's a service part. I'm under the assumption that there was a resistor plate between the two metals inside, which burned away. If I press one metal down to the other I only, I'll only get 0.2 Ohm, but should be 10 or 20. Also, if I shake it, something moves inside the top, but the whole thing doesn't react to fire or heat from a stove. So it seems to be FUBAR.

>> No.1902328

Yep that worked
Thanks for listening to me waffle on

>> No.1902369

Not so sure anymore that it is broken. I made it react to heat, just needed more of it. Would it be a mistake to put some 11k Ohm resistor between the contacts until it heated up, before removing it while having the machine plugged out? If that's even necessary, I think it's not for the water but to prevent it from overheating. It's all a bit confusing.

>> No.1902370
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Anyone here into RF/HAM? I got one of those SDR dongles and they came with a set of 'bunny ears' antennas.
How do I calculate the proper length of antennas for a given frequency? How much do I have to extend them?
Also, should these types of antennas be spread apart? is there an optimal angle between the two whips?

>> No.1902374

1/Frequency gives you the the measurements (wave length) ....they are usually spread apart becase you get better coverage depending if the signals are coming from east or west ....also keep in mind the wave propagation for that kind of antenna is a cylinder not a ball (you dont turn the tip towards the signal like people might think)

>> No.1902375

>>190236unless its snapped or broken it should still react to heat ...the thermocouple inside gets warped or loses its elasticity from long usage and doesnt regulate on the proper temperature ...get a new one ...spend the 10 $ on the new one dont be a cheapskate ...some things are not worth nigger rigging

>> No.1902422
File: 138 KB, 1632x1224, 1596481334974.jpg [View same] [iqdb] [saucenao] [google] [report]

pcb holders and third hands... what do you guys use/recommend?
I have nothing and use a pair of pliers and a clamp to grab on shit. I'd like to get something that works better than this method.
any suggestions?

>> No.1902438

ffinger dexterity and just fucking around with different clamps until you find one that works for you ...there is no real all in one package because everything depends on the board and component sizes ...i have a whole lot of holders from workshop vices , homemade holders and jigs , the chinesium crocodile clip things , watchmaker vices and holder , the big benchtop thing that has the foam that holds components in place for production run soldering etc ...tell us what is your biggest problem / use case so we go from there

>> No.1902439
File: 17 KB, 344x240, dipole.png [View same] [iqdb] [saucenao] [google] [report]

That looks like a dipole antenna. Each ear is one quarter of the wavelength. The wavelength is 300/f, frequency in MHz length in meter.

>> No.1902442

>1/Frequency gives you the the
the time of one cycle

>> No.1902449

>tell us what is your biggest problem / use case so we go from there
soldering connectors to wires. it's damn near impossible without some kind of a device.

>> No.1902453

tin both sides, hold them together, and reflow them

>> No.1902458

sure, but that's not so easy in practice when the wires are small and connector pins even smaller.

>> No.1902484

It's a 60A motor driver with 3 parallel MOSFETs. I already did the calculations, and according to a simulation what I just built should be almost as good as the driver that's burnt out.
It's a semi-urgent replacement and what with the current situation it's unlikely that I can get a dedicated motor driver from anywhere, so I'm stuck with local parts and parts I already have.

Darwinism. Convince him to go to the doctor for a lead intake test, hopefully that's hassle enough to prevent him from doing it again.
People reading signs is surprisingly difficult to ensure, it's much better to put some sort of lock or issue with the mechanism itself to stop people using it unconsciously. Removing the fuse would be a good cheap method.

But the guy said 1000µF=1mF at 1A. But that calculates as 10V of ripple. You're saying 10mF means 1V of ripple, which is concordant with this.

>> No.1902488

desu i just use whatever vice or holder to keep the connector in place tin the wire and conenctor the use one hand to solder and the other to hold the wire ...or try findig some jewelrs or watchamkers jigs ...which are basically high quality aligator clip things

>> No.1902499

if you can choose find MOSFETS with the least ammount of gate charge ..the current is proportional to the (charge)x(switching frequency)x(number of MOSFETS) so the smaller the gate charge the smaller current it needs ..also you can find very low Rdson (can handle more current) for pretty cheap so you dont need as many in parallel and they dissipate less heat ...i think i had some ST55 or something MOSFETS with miliohms Rdson and can handle 60 amps by themselves

>> No.1902503

skilled people slowly exhale
quiet hand - quiet mind

>> No.1902508
File: 10 KB, 494x400, 1582927497022.png [View same] [iqdb] [saucenao] [google] [report]

all right, post a video of you doing it without any accessories.

>> No.1902510

The MOSFETs are already in place, and the same argument against getting a MOSFET driver applies to getting new MOSFETs as well.
The FETs are IPP023N10N5 transistors, which are rated to 120A, 2.3mΩ when on. Gate charge is 168nC. Don't know why there are 3 in parallel, but I'm keeping it safe because it's a DC motor that will likely pull a lot more than 60A when stalling and starting up.

If I do replace the MOSFETs, I might as well just replace the entire PWM driver board. Which is far larger than it needs to be. Not sure what kind of safety shit is programmed into the PIC though.

>> No.1902527
File: 684 KB, 2048x1536, DSC_0304.jpg [View same] [iqdb] [saucenao] [google] [report]

Just pulled this beautiful VFD & vintage COP470 driver IC + miscellaneous components from some old PCBs. Have you ever tried to drive a VFD? Does it require high voltages?

>> No.1902566
File: 69 KB, 1500x952, Amtech S1751 Lead Free Solder.jpg [View same] [iqdb] [saucenao] [google] [report]

>soldering connectors to wires.

roll up some solder into a coil, put it inside a pill bottle, which you hold in your mouth.
(there's a special way to wind it so it doesnt become entangled, but it's a secret i cant share with just anyone)

>> No.1902579

>Does it require high voltages?

kinda. youtube has various how-to's. search ''How to control a salvaged VFD (Vacuum fluorescent display)'' for example.

>> No.1902673

This is some interesting stuff, I didn’t know they made ICs like this.

>> No.1902683

That's pretty cool, shame it's so expensive.

>> No.1902708
File: 69 KB, 850x650, How-to-Tie-a-Double-Fisherman%u2019s-Knot.jpg [View same] [iqdb] [saucenao] [google] [report]

How much hotter than the contraction temperature of heatshrink do you want your hot air gun to be, is +50C good?

I just had an idea... you know how solder joints to stranded (and unstranded) cable can become weak it they are moved a lot because the point where the copper flexes is right on the edge of the solder... it just occurred to me, instead of soldering lengths of stranded copper wire together why not twist each of them and then tie them in a reef knot? If you tie a reef knot which is two granny knots then the left strand will come out of it and lay back on itself, as will the right strand, but if you make a triple reef knot with three granny knots then the left strand will come out of it to the right and visa versa, you could even twist the strands coming out of the knot around the incoming wire a little to make sure there's lot of surface for conduction, then heatshrink. Mechanically and electrically sound, maybe more sound than a solder joint that may weaken if it is flexed.

A double fisherman's knot might be good too, pic related

Anyone know where you can buy heatshrink that is conductive on the inside, I might wanna use it for making such tied connections, but can't find it in New Zealand. Although you could maybe cover such a connection with foil before applying the heatshrink for a similar effect.

>> No.1902710

my fellow african

>> No.1902727

What's the best cordless soldering iron on the market?

>> No.1902763

Why did we give up leaded solder again?

>> No.1902768

>heatshrink that is conductive on the inside
It almost certainly doesn't exist. Metallic substances and substances that undergo permanent deformation upon heating are likely mutually exclusive. But there are heat-shrink solder splices at jaycar. Just stick a wire in each end, heat it up with a lighter, and the solder in the middle will reflow over the two ends of the wire while the heatshrink shrinks.

As for the knots, a linesman splice is probably as strong as you're reasonably going to get. The point of a knot is to maximise the friction force between ropes to stop them from slipping free, and to arrange them such that this friction force will increase as the force increases. This static friction force is proportional to the force with which the ropes are being held against one another, but this doesn't apply to the force behind a solder splice. The solder joint itself will have a retention force proportional to some combination of the area and inverse separation, hence to maximise this you just need to maximise the area of copper. No self-enforcing friction loops required, just turns that wet with solder.
It might make more sense if the tension was being held by the insulation and not the copper, but in most situations the insulation will stretch easier than the copper, making the copper the load-bearing element.

A corded soldering iron with a DC barrel jack bodged after the internal power supply. If it's got an SMPS in it you could just run it directly off a high enough voltage from a battery array.

Because boomers' kids started soldering, and they didn't have any prior exposure to lead due to unleaded petrol, so we could actually get a before and after of the IQ drop.

>> No.1902774

just did my first soldering job today and it worked. thanks bruds.

>> No.1902777

noo you forgot the fluxerinos

>> No.1902785

? Never did, never will

>> No.1902854

Quick question about interrupts on chips. If I disable all interrupts, how can I keep track of how many milliseconds have passed.

>> No.1902861

>how many milliseconds have passed
From when to when?

>> No.1902895

I need a transistor so that when signal S turns to 5V, it connects A to B. How do I choose? PNP? NPN? MOSFET? My preference will go to whatever is the most easily available.

A --- 12V
B --- Ground
S --- 0V or 5V

>> No.1902903

>it connects A to B
Which way will current be flowing from A to B? Because NPNs and PNPs only pass current in one direction and muddy the output signal with their own base current and voltage drop, while MOSFETs have an integrated diode in antiparallel with them that will pass any reverse signal that can get past its -0.7V drop. The only transistor that works here is a JFET, but they're comparatively expensive and a slight pain to drive.
Thankfully, there exist dedicated analog switch / analog multiplexer ICs, like the CD4051, 4052, and 4053 trio. Possibly cheaper than discrete JFETs and more versatile. I think they use MOSFETs inside, but either in configurations that prevent asymmetry or taking advantage of some sort of alternative body connection.

>> No.1902907
File: 7 KB, 400x400, tegaki.png [View same] [iqdb] [saucenao] [google] [report]

If it is just a switch that carries current in one direction however, you just want a simple BJT or MOSFET. If you're switching more than 100-500mA or so I'd use a MOSFET, else use a BJT. You want to use common-emitter / common-source configuration, i.e. your NPN goes on the low-side or your PNP goes on the high-side. Note that a high-current MOSFET won't turn on fully at only 5V, which matters if you're switching 10s or 100s of volts.

How much current can you pull from S? Because BJTs (NPNs and PNPs) take base current to turn on, say 50-200 times less current than the maximum being switched. MOSFETs on the other hand don't consume any current through their gate.
Also how much current does your load have?
>inb4 you just want to short 0V to 12V

>> No.1902909

When A is grounded it remotely opens the door to my appartment complex. I guess current will flow from B to A? MOSFET seems to be the best solution since there's no need for precise signal, just short out A

>> No.1902913

>current will flow from B to A
A is positive so it flows from A to B
>just short out A
this sounds bad
are you sure you don't want to interrupt the current flow to something instead of shorting it?

>> No.1902917

having trouble getting a current reading
I fell into the >inb4 before seeing it hehe

A is constantly set to 12V by a remote source. When you press the key button, it grounds A to 0V, thus opening the door.
I'm trying to recreate that effect but triggered from the signal sent by my outside button.

>> No.1902950


>> No.1902967

i found this old resistor and its just a wire going through a concrete block. very weird.

>> No.1902997

That isn't concrete.

>> No.1903003

ah. probably is. no harm done since im not souking it.

>> No.1903005
File: 52 KB, 632x482, resistor-wattage.jpg [View same] [iqdb] [saucenao] [google] [report]

Not necessarily old, just a high power resistor

>> No.1903009

looks similar to the bottom right but the wire is exposed.

>> No.1903025
File: 48 KB, 625x625, 201907091731115275505.jpg [View same] [iqdb] [saucenao] [google] [report]

Then it might also be high precision

>> No.1903119
File: 44 KB, 750x750, HTB1f1huNhnaK1RjSZFBq6AW7VXaP.jpg [View same] [iqdb] [saucenao] [google] [report]

I made a circuit which consists of 2 attiny85 and a atmega34u2. They're all connected to the pc through an integrated USB-HUB on the PCB.

I use the HS8836 for the hub, which is found on most cheap chink usb-hubs, but I keep the driver error code 43 on windows. I tried to force the generic-usb drivers on it but it won't do. Any experiences with chink usb-hub ics? The IC is very close to the usb plug and the traces are of the same length.

>> No.1903121
File: 124 KB, 800x665, Unbenannt.png [View same] [iqdb] [saucenao] [google] [report]


>*I keep getting

Here is a snip of the PCB in case you see something weird.

>> No.1903125

Those rates are super low at zero duct length.

Look for a flow rate at least 2x the slpm of what you are spraying

>> No.1903127
File: 27 KB, 251x236, fugisdismeng.png [View same] [iqdb] [saucenao] [google] [report]

What's this little guy all about

>> No.1903129

nm, it's the silkscreen/ ref whatever.
Turn off all the non-copper layers please

>> No.1903130
File: 62 KB, 672x586, Unbenannt.png [View same] [iqdb] [saucenao] [google] [report]


Here. There are some copper layers on the other side too but it's all about the usb-hub.

I believe I just got chinked with the firmware or something. I thought about using one from a real usb hub but those are mostly hs8836A with another pinout and changing all the traces now would be a pain in the ass.

>> No.1903131
File: 70 KB, 638x585, Unbenannt.png [View same] [iqdb] [saucenao] [google] [report]


This is what you've been seeing

>> No.1903135
File: 172 KB, 1279x678, 20200829_145102.jpg [View same] [iqdb] [saucenao] [google] [report]

This is a 8 pin electron gun from a CRT TV. Does anyone know what this part of the electron gun is for and what does it do? Is it related to the final anode of the TV (The one that connects the glass to the transformer)?

>> No.1903142
File: 102 KB, 1000x1000, 2 in 1.jpg [View same] [iqdb] [saucenao] [google] [report]

My main iron is a TS100 with a hoof tip, would something like link related be an improvement for large jobs like motherboards?

>> No.1903151
File: 181 KB, 793x671, bodgeable?.jpg [View same] [iqdb] [saucenao] [google] [report]

So uh... is it advisable to bodge this broken pad/trace across this short gap? (2-4 mm?) Or should I go the safer route and run a bodge wire roughly 5 cm to where it's going?

>> No.1903173

Why are those two connectors on the bottom sharing lines?

>> No.1903174

route from pad to pad unless you have no choice.

>> No.1903179


The 4 pins? They're optional in case you don't want to solder the usb plug directly on the PCB, instead somewhere else, But for the prototype I soldered it directly.

>> No.1903187

Would this be a cool beginners project?

>> No.1903193
File: 211 KB, 1842x1147, yihua.jpg [View same] [iqdb] [saucenao] [google] [report]

That's a fucking long link, are you trying to beat the 4kB GET payload limit?

I never worked with a TS100. I have a chink 852D+.
852 is the entry level, temperatures are quite approximate, heat conduction to the tip of the iron is not as good as I'd like it to be. I mean, it works, but you really see that it's a cheap one.
Hot air works similarly - temperatures are not real but are repeatable (I mean when you take a pyrometer, it displays a different value than the dials, but for given settings and nozzle the readings are consistent). Lowest blow force from the hot air is able to blow away SMD resistors.

Motherboards? Aargh. Motherboards are hard to solder in general, they typically have far to many layers that can dissipate heat and use a cheap high temperature lead-free solder. 852 has enough power to give it a try, but get right tips.

>> No.1903194

that fucking link

>> No.1903204

I got it. It lined up pretty well with the theory. 72mhz with 32 bits mines I can count cpu cycles for 59 seconds before it restarts. So I just have to check the clock counter at least once per minute.

>> No.1903217

fixed your link friend:

Maybe a little bit of advanced pain to solder the cube itself, but it comes with a PCB which should be easy enough to solder. I'd get a soldering test board first if you're unexperienced with soldering onto PCBs however. Can also get some pretty cheap SMD ones.
A more common beginner project is the simple LM317 power supply board, so much so that I've seen it being used as a benchmark for how fast you can solder.

>> No.1903239

Hello electrofrens,

How do I go about wiring up a stepper motor so that it runs off a plc? I know that I need a stepper motor driver, but I really don't know how else to do it.

>> No.1903248

I can usually read minds to get relevant info like part numbers or pictures, but for some reason I'm having trouble reaching yours.
However I consulted some chicken bones and can guess that PLC outputs -> motor driver inputs

>> No.1903251

Well gentlemen, after damaging the sockets on my board, destroying traces and pads desoldering them, *three* orders of parts from Mouser, and having to learn how to bodge shit...

My Apple II disk drive boots.

It still won't write for some reason. But it boots. Which for me is a small fucking miracle. I was expecting the damn thing to go up in smoke as soon as I plugged it in.

>> No.1903262

>My Apple II disk drive boots.
Good. Keep at it and you'll fix it.
>It still won't write for some reason.
Make sure the write sensor is functioning (where the WP notch is cut into the disk when fully inserted into the drive).

>> No.1903265

>Make sure the write sensor is functioning (where the WP notch is cut into the disk when fully inserted into the drive).
Yeah, it's the damnedest thing. This was what was going wrong when I broke it. The thing is, it's one of those duodisk setups (two drives controlled by a single analog board) and the same shit happens on both drives. i suppose it's possible that the w/r sensor on both drives is fucked, but i replaced all but two ICs on the board (one of which has nothing to do with writes, and the other... I'm not sure what it does).

Ah whatever. For me, it's Miller time. I'll look at it again tomorrow.

>> No.1903267

>possible that the w/r sensor on both drives is fucked
If that is indeed the case, you can just install a SPST switch to toggle the WP on/off manually.
>For me, it's Miller time.
Don't spill any beer on your disk drive. lmao

>> No.1903269

>trying to beat the 4kB GET payload limit?
What? I thought GETs were dubs and trips.

>> No.1903285


I'm talking out of ignorance, but most industrial PLC enviorments use some short of drivers and libraries, such as SoftMotion. You still need a driver as you said. Can you specify what you're using, specially the controller?

>> No.1903287

>LM317 power supply board
thanks man, the seller also has that so I will do the psu first and then the lights.

>> No.1903345

>>heatshrink that is conductive on the inside
>It almost certainly doesn't exist.
It does actually, there is heatshrink with a metal mesh liner https://www.cablesmanager.com/heatshrink-tubing/2-1-conductive-interior-dual-wall-shielding-heatshrink-tubing
And conductive heatshrink designed to shield EMI https://www.electriduct.com/2-to-1-Conductive-Heat-Shrink-Wire-Connectors.html

>> No.1903346


So, would that be a discrete output or an analog?

>> No.1903352

It may be possible to connect a standard driver or speed controller up directly to your PLC if it was made with such (probably serial) connections in mind. But if not, you'll need some way of converting simple signals that the PLC can send (i.e. parallel speed value, forward/reverse bool, brake/freewheel bool, etc.) and convert them with some sort of adapter circuit. This could be as simple as a single DAC or as complex as an MCU, all depending on what kind of control input your stepper driver expects.

Nice work! It's real interesting hearing about this sort of endeavour, back from the days where building usable computers was still an electronics project.

>a metal mesh liner
Didn't think about that, interesting
>designed to shield EMI
Now THAT's useful sounding. Especially for bodging about with coax, though I guess I should just be crimping BNCs or whatever and using off-the-shelf splitters and such.

>> No.1903355

>Nice work! It's real interesting hearing about this sort of endeavour, back from the days where building usable computers was still an electronics project.
I honestly can't believe it was able to load data from any disks. I had to do something like 150 solder points and had to bodge 4 or 5 different connections I'd damaged. Plus the new ICs didn't want to seat in the DIP sockets properly, so I had to (carefully) bend the legs inwards.

Out of I think 12 ICs I replaced 10 (considering how cheap they were at Mouser it would've been silly not to). The two I didn't replace are out-of-production and there's no obvious substitute, and I didn't feel like waiting two months to get god-knows-what from China.

But... it's a real thrill that it booted and loaded data. From what I learned about how the drive works, there are any number of places where the read operation could fuck up.

>> No.1903360

oh, i see. no motor, no controller, well, good luck anon, no fucking way I'm wasting my time here, I'm not a dentist.

>> No.1903424

thanks anon!

>> No.1903431

Can you lads recommend a decent starter oscilloscope?

>> No.1903443

Buy a 2nd-hand analog oscilloscope. Better and cheaper than a new scope in most cases.
>inb4 you're in brazil

>> No.1903457

Nah, in the US. I've looked for analog scopes on eBay. I have no clue what shit's supposed to cost or how to tell a decent one from a dud. I've seen EEVBlog's video on picking up a cheap analog scope before but it honestly feels like every time I look I just find shit that needs fixing (and I don't know how to fix) or shit that I can't tell is any good.

>> No.1903460

tektronics are abundant. You can pick them up for less than 200, even 125.
Check that the focus works, that the first thing that goes.
You want to check that the smallest resolution waveform can still be picked up. You can do that with an arduino programmed to do a 1/255 duty cycle pwm. If you can see the high and low clearly, the scope is working.
If the focus is good and it can still show that resolution, chances are very good the scope is OK.

>> No.1903461

Doesn't really matter what the specs are so long as it's got at least 2 channels, an external trigger input (third BCN input on the front), and it works.

Damaged scopes are really hit and miss, while they could be a fun project, they could also just be you desperately trying to find a replacement CRT for cheaper than you bought the scope. Unless you already have a scope for troubleshooting, I wouldn't try a broken scope unless you have a good idea of what's broken and can find its service manual online.

t. got a really good scope for free just by snooping about my university

>> No.1903462

A lot of stuff that's listed as "for parts or not working" is actually working fine it's just the seller doesn't know how or have the capability to test it. Might be stuff they acquired from some business closing or something and they're just looking to dump it. They list it as not working so they don't have to take take it back if it actually is broken and the buyer wants to return it. You'll usually get scopes cheaper when they're listed like this. If you want something more likely to work there are stores that sell test equipment on ebay. They typically test it though they usually sell at a bit of a markup. You pay for the convenience. You'll usually want to check for pics of it being powered on and probably get one that's not in completely horrible cosmetic condition. A few minor defects are fine but serious defects are probably something you don't want to deal with.

If you don't want to be arsed with that then a good starter scope would be the Rigol DS1054Z or Siglent SDS1104X-E or similar. Price is around $350-400.

>> No.1903519

> What? I thought GETs were dubs and trips.
Sorry, I'm too biased towards /g/. What I meant is the limited length of a "link" in a HTTP protocol GET method.
When you open in your browser a link in form 'http://domain/location?arguments', then it sends a HTTP request to the 'domain' containing a line 'GET /location?arguments HTTP/1.1' (for http1.1, which is obsolete albeit dominant).
Typically this line has a length limit in web browsers and web servers.
For instance IE cannot handle any link beyond 2kB, edge fails to use links longer than 4kB, while firefox and webkit based (e.g. chrome) let you type 64kB.
This means that if you make a link that is too long, it can work fine in, say, vivaldi browser, but won't work in edge. I did encounter once a link long enough - search filters on an electronic parts supplier, where all possible options went to URL upon selecting "all above this value". They changed it already.

>> No.1903521

So, I desire to get a basic idea of the things that defines our world and living. Like, after my studies in laws I feel like I understand (world) events and their impacts so much better (I worked a while before I studied).

Please, if you are an expert in any field and feel like a certain book would help an outsider to understand the world or the corresponding field, share (History, Physics, Biology, Arts, Craftmanship, Medicine, etc.).

Thank you very much.

I´ll start off with something not specifically my field but I am working in management:

Thinking, Fast and Slow by Daniel Kahnemann

>> No.1903523
File: 710 KB, 2048x1536, Photo0529.jpg [View same] [iqdb] [saucenao] [google] [report]

imagine using a laptop and not rebuilding scavenged PC's from the junk yard or scrap collector.

>> No.1903527

What would happen if I connected a capacitor in between a speaker and an amp?
Just +to the amp side and - to the speaker side.
what if the capacitor was 2F... not a typo...

>> No.1903528
File: 50 KB, 960x516, what you are doing to yourselves.jpg [View same] [iqdb] [saucenao] [google] [report]


>> No.1903531
File: 237 KB, 598x792, identifying arguments.jpg [View same] [iqdb] [saucenao] [google] [report]

the art of electronics by Horowitz and Hill
this interview with Jodan Peterson
and every book by Stefan Molyneux
inb4 cultist
inb4 debate

>> No.1903532
File: 20 KB, 505x689, unknown.png [View same] [iqdb] [saucenao] [google] [report]

Is there any reason why it may be ill-advised to salvage lipo batteries from old or unused devices for use in personal projects? I just figure there are many around in old tech that surely have a decent amount of life left in them. Seems like a waste.

>> No.1903536


You can't just wire a servo to an output and make it work. Servos work with specific pwm signals which most PLCs can't deliver, hence the drivers.

>click PLC

I've never seen those but if you go to their website you can see they offer motion control hardware. Read their manuals, but I suggest you to check general basics on youtube first if you have no prior experience


If it's just this one project you have and don't have that much interest in learning go google "clearPath-mc" servos, they are much easier to operate.

>> No.1903540

It's a good idea, but you need a good way of checking whether any cells are bad. With an 18650 array, you can test individual cells and replace the bad ones, but I don't know about monolithic series lipos. If they're 1S or otherwise working, go for it. Might want to go a little conservative on the charge-current though.

>> No.1903545
File: 181 KB, 1280x720, maxresdefault.jpg [View same] [iqdb] [saucenao] [google] [report]


I would also like to add: I would avoid these obscure off-brand PLCs. If you're doing it privately as hobby and got those because of the price just go straight for Raspberry Pi, it's compatible with CodeSys which is a very common PLC-Software after Siemen's TIA. And even the PLCs which don't use CodeSys directly use their own fork of it (Beckhoff, Festo etc.). So you would be learning how to program many PLCs at once.

If you are indeed doing this profesionally there are still cheap PLCs with CodeSys.

>> No.1903546

>Just +to the amp side and - to the speaker side.

so, in series. nothing would happen. speakers work on AC, so a 2F cap looks like a teeny weeny lil resistor in series. in the micro-ohms.

>any reason why it may be ill-advised to salvage lipo batteries from old or unused devices for use in personal projects?

yes, if they're unused it's most likely coz they're nearly dead. lots and lots of gadgets get thrown out coz replacing Lipos is impossible or too expensive.

>> No.1903636

industrial society and its future

>> No.1903639

A History of Central Banking and the Enslavement of Mankind

It's banned on amazon but you can get it at Barnes

>> No.1903642

Depending on your speaker impedance and capacitor rating, a single capacitor in series acts as a (bad) high pass filter. Some cheap speaker setups use a simple cap as a "bass blocker" on the tweeters so they don't get the really low frequencies, which may damage them.

As far as what 2F would do, not much. You calculate the crossover frequency with:
F = (0.159)/(C*Rh)
Where C is the capacitor in microfarads and Rh is the speaker impedance in Ohms.
Assuming a 4 Ohm speaker, a 2F capacitor will make a highpass filter at 0.02Hz

>> No.1903645

I have an old electric smoker, had a control panel where you can set temperature, time, etc. but due to sitting outside for years it's gotten pretty flakey and will often just shut itself off.
Is there anyway to just rip all that shit out and replace it with like a simple on/off switch and maybe a dial for temperature? Don't need a timer or anything fancy.

>> No.1903665

You might need to replace the heating element.

>> No.1903666

I threw one of those smokers away a couple years ago because the electronic controls flat out failed. I got the impression that fixing the particular failure would've required tearing out all the electrical shit from the smoker box itself and not just replacing the control panel. And I fucking covered the thing when it wasn't in use. Got two years use out of it and it fucking died. I've never been so angry.

I need to build a fucking smokehouse one of these days, but I don't know shit about concrete, masonry, or carpentry.

>> No.1903674

>I need to build a fucking smokehouse one of these days, but I don't know shit about concrete, masonry, or carpentry.
Thank god you're on the internet

>> No.1903677

First you must learn how a DC (direct current) motor works and then know that a stepper motor is not DC motor, you need an Intelligant Driver. Also I=V/R. Current kills a motor. Get Allen Bradley PLC and nice source, use software EasyPLC and connect wires (red = 1, blue = 2 and black = 4) and vice-versa and use software EasyPLC for configuration for Modbus & Profinet. Learn the difference between 12V and 24V it will save your life trust me. Good luck.


>> No.1903679
File: 44 KB, 480x480, 1590660402059.jpg [View same] [iqdb] [saucenao] [google] [report]

poast unibrow

>> No.1903683

Truth be told I've found plans. I just don't have the confidence to build the fucker.

>> No.1903685

Nobodies going to laugh at you if you fuck it up the first time, but you're going to hate yourself for still wanting to build that smoker 2 years from now

>> No.1903687
File: 32 KB, 1000x578, sena sc1.jpg [View same] [iqdb] [saucenao] [google] [report]

I'm coming here from /o/ with an idea for a /diy/ project because the product at hand is sold at a ridiculous margin.
The item in question is bluetooth comms.
I have a schuberth helmet which can integrate pic related but it's 200€.
Now I'd like to make a bt module + amplifier that fits into a 3D printed enclosure to insert into the helmet + a small battery pack.
I'm looking into https://www.qualcomm.com/products/csr8645 as an SoC to use and develop a custom board, maybe even reverse engineer some cheap bluetooth earphones that use this chip. With a decent lithium battery I'd comfortably get 8h+ of talk/music time.
I have the soldering equipment and a skilled person at work and if I make a prototype on a breadboard it would only need programming (I have plenty of friends who I'll force into programming for a case of beer).

With that out of the way I'm open to any and all suggestions for this project.

>> No.1903691
File: 44 KB, 691x444, flex pcb.jpg [View same] [iqdb] [saucenao] [google] [report]

I'd keep the battery on the outside of the helmet with waterproof connector for power and neodymium magnets to mount it.

>> No.1903695

If you need a programmer why not partner with a friend who can program rather than jew him for beer?

>> No.1903700

poster is probably a college student studying business and thinks that's how the world works

>> No.1903714
File: 332 KB, 1080x1440, c4 pro.jpg [View same] [iqdb] [saucenao] [google] [report]

Helmet has two compartments. Red is for comms and blue is for the batterry.
I'd put the battery into the 3D printed housing that locks with the existing tab in the compartment.
I haven't thought about waterproofing yet but it definitely needs it.
The programmer thing was meant as a joke. I have no intention on selling that shit. If it works I'll give them out to my riding buddies. I think I could definitely make them for under 50€ in BOM.
I'm a CS college dropout and my friends will help me when I'm stuck on something.
FFS I successfully implemented real time 3D audio in C++ during college, how hard can a bt connection with a phone be. I'm rusty as hell but I still have all my projects saved.

>> No.1903727
File: 27 KB, 792x394, Capture.jpg [View same] [iqdb] [saucenao] [google] [report]

do you have friends that work with embedded? if not then "help me when I'm stuck on something." wont work. In theory you could do it yourself but it would require hundres of work hours and no offence but you dont sound like a person that is dedicated enough. Only do it if you are genuinely interested in learning stuff as overall its WAYYYYY cheaper just to buy the 200 dongle for yourself and your buddies

>> No.1903736
File: 38 KB, 800x800, kz bt cable.jpg [View same] [iqdb] [saucenao] [google] [report]

I have a friend who does low level stuff for drones, cameras and other military stuff.
>and no offence but you dont sound like a person that is dedicated enough
Shit man, you might have hit a bullseye here
I've tried to make a servo motor steering wheel in the past and got USB HID drivers working through an STM F3 board but the servo motor was shit and didn't track steps correctly and it spazzed out so I abandoned the project.
>your pic rel
Oh shit, didn't see that before. Well, guess I'm fucked if there's no freely available documentation.

Well this is why I come here. So you can pull me back into the real world.
I guess the better/ thing to do would be to buy a bt cable (pic related) and dissect it so it would wire into the existing headphones and mic in the helmet. Maybe even upgrade the battery.

>> No.1903804

Such a BT cable may well be the best solution. Ask on >>>/g/iemg/ or whatever it's called, IIRC an anon there found surprisingly cheap MMCX BT cables like that, like half the price of the KZs or TRNs.

But we're getting to the territory where it would be easier to just use an intact BT cable and replace the connectors on your speakers to MMCX. Assuming they work while the USB charge port is plugged in.

>> No.1903882
File: 69 KB, 437x403, 1510050820833.jpg [View same] [iqdb] [saucenao] [google] [report]

I've started getting into this during the summer, I read Mims and have done a few soldering jobs successfully. I want to learn KiCAD for PCB design now, is there a go-to resource for learning PCB design you'd recommend? I eventually want to work with MCUs and think I need to do 4-layer.

>> No.1903885
File: 15 KB, 298x400, Two UHF 2-Way Radios (Walkie Talkies) and. Uses standard 2 Prong Kenwood plug for the headset.jpg [View same] [iqdb] [saucenao] [google] [report]


bluetooth is notoriously finicky and short range. i'd just get some walkies with headsets and stick it in my breast pocket. (i probably have a dozen i found cheap at the thrift store.) you'd need to wire an external PTT button, or rely on a VOX setting (starts to transmit when you start to talk - with a minor delay). bonus is you can have unlimited people on the same frequency, so all your leather-clad bros can share their impressions of hot guys as they pass them on the street.

>> No.1903990

>is there a go-to resource for learning PCB design you'd recommend?
no. learning any pcb software is going to be a miserable frustrating process. they have a ton of overhead to accommodate all of the weird shit that their enterprise customers use like 32 layer boards with 1000 components and fine pitch BGAs and impedance matched buses. you'll just have to bang your head against it until you learn what buttons to press. just be glad you're not using fpga software.

>think I need to do 4-layer.
depends. if you're doing non-bga mcus below 100MHz and you're not packing your board full of shit (guaranteeing it won't work) then 2 layers is fine and a fair bit cheaper.

>> No.1904014

>learning any pcb software is going to be a miserable frustrating process
Well I’m using KiCAD just fine after just watching a 1-hour tutorial. Sure I don’t know all the particulars, but it’s perfectly usable for what I need it for.

>> No.1904016

Thanks anon, good information

>> No.1904017

good luck. i use altium so maybe it's worse in that regard, but i get the impression that all of the programs are similar.

>> No.1904037

wow what the fuck is with these low-end digital scopes having like every fucking function requiring a license key for $125?

>> No.1904038
File: 133 KB, 1280x720, maxresdefault.jpg [View same] [iqdb] [saucenao] [google] [report]

Different anon here.
I didn't know Pi's are compatible, that's neat.

As a college project, we are building a PLA shredder. The machine must abide by all relevant regulations/standards.

Right now I'm working on a subsystem for detecting jams (measuring speed would be nice too). Pretty sure a jam would lead to the motor overheating, which I guess is pretty bad.

The approach I'm thinking of is building a of tachometer of sorts, using an inductive proximity sensor. Idea is to to watch for passing gear wheel teeth.
Not sure how to implement this on the software side yet (Siemens PLC + CodeSys).

1) What are your immediate thoughts?
2) I'd rather not solely rely on the PLC to prevent overheating. What safety redundancies can I use?
3) Is my approach good or should I ditch it in favor of some better solution?

Any input is highly appreciated. It's very hard to find relevant resources (especially when it comes to the regulations/standards part).

>> No.1904044

>Licence Key

>> No.1904047

I wouldn't use bt as a way to communicate. Bt is just a way to connect the headset to the phone. Then the phones are connected together through any of the thousand voice chat apps.

>> No.1904052

These entry-level oscilloscopes like the DS1054Z. Many of the options on the scope lock out after 30 days and require a license key after that. No shit.

Sure there's cracks out there but what the actual fuck?

>> No.1904071
File: 13 KB, 380x380, 1544877822885.png [View same] [iqdb] [saucenao] [google] [report]

>found a couple of SLA emergency lamps with toast batteries
I have a few questions:
Will soldering a leg back onto a small halogen bulb cause it to crack or explode?
Do I have to use a bulb of a certain voltage, or does only wattage matter? (This bulb is 6 volts, 10 watts).
Is there a high-output LED that will take 6+ volts DC so I won't need a driver?

>> No.1904081

>Will soldering a leg back onto a small halogen bulb cause it to crack or explode?
It's probably fine if the leg is long enough and you get in quick. People solder onto vacuum tubes after all.
But I would go with an LED.
>Do I have to use a bulb of a certain voltage, or does only wattage matter?
Voltage is what matters, but an LED with no driver won't run off a constant-voltage supply like a battery, or at least not for very long. You'll want a driver of some kind.
>Is there a high-output LED that will take 6+ volts DC so I won't need a driver?
How high output? 1W and 3W single-LED packages are relatively common (piranha LED?), can probably find a table to compare one of those to a 10W halogen, but I'd say 3W would be at least as bright. Might need a heat-sink though.
Any single-LED package will have a forward voltage of 3-4V, so there's room for a driver to step-down the current. An LM2596 constant-current buck converter should work well here, though if you're not concerned about power consumption you could use a resistor or LM317 instead.

On the other hand, you may be able to find 6V motorcycle LEDs that are ready to plug into your battery with no peripheral circuitry.

>> No.1904098
File: 458 KB, 1426x550, file.png [View same] [iqdb] [saucenao] [google] [report]

tiny boards are the most fun. this is a cr2032, a pic, a 7 segment, and a humidity sensor.

>> No.1904100


>> No.1904126

>tiny boards are the most fun
Agreed. Are those what castellated vias look like in KiCAD's 3D viewer, even with appropriate edge cuts?

>> No.1904213

I'm not big into PLC so I'm not sure what the limitations are for different systems.

But your best bet is to make a list of all the regulations it needs and work to satisfy them all. Some concepts will be nearly the same, so you can combine functions.

As for overheating, I typically monitor motors four ways:
1)Measure voltage for the motor (or multiple voltages, depending on motor design)
2)Measure current for the motor. Same as above, but you're looking at amps, not volts.
3)Motor speed - easy to read with an encoder, hall effect sensor, ect...
4) Actual motor temperature. This one can be tricky, because a rotor can start overheating before the stator. Again, this will vary by motor type.

You can monitor all those variables to decide if the motor is outside of normal parameters. If the motor should run at 48V, 10A under load, you can watch for a voltage drop or current jump and react accordingly. If something gets sucked into the machine, the motor may pull excessive power to keep going. You may not detect it slowing down (or not very much), and it would take a while to overheat. But an instant spike in current? You can act quickly on that.

>> No.1904226

putting MOSFETS in parallel helps with distributing current by putting a third thorugh each ...they heat up less basically which is good ...that gate charge is huge tho but not unusual fot high current MOSFETS with low Rds but there are better ones nowadays but depends on thde price

>> No.1904227


>> No.1904231

That's the neck tube. The pins are the inputs the monitor board sends (highly amplified) signals to. The electron shoots out of there, and hits a grounded mesh that's covered in phosphor, which lights up.

>> No.1904243

What bandwidth oscilloscope do I need for doing retrocomputing shit? When do you need to make the leap from 100 MHz to something higher?

>> No.1904248

god damn it sometimes borwsing this board is hard as fuck to not get pissed at people that want to learn. I personally feel the pain of knowing so little that you dont even know how much you are missing...but i feel there should be a sticky with a guide to giving relevant information about building projects.

relevant information needed from your side is >what kind of stepper motor is it
bipolar and unipolar stepper motors have entirely different drivers for them and how many input wires does it have, also some are constant voltage driven , some are constant current driven
>available input voltage and current
>what kind of PLC do you have and what are its output voltages and currents
>do you want it out of discrete parts or do you plan on buying integrated solutions

>> No.1904253

buy a 4 chanell RIgol DSO with around 20MHZ bandwith with a few math functions and few different kinds of triggers. It should cost about 300-600 dollars and is a better thing for a beginner than any analog scope that has absolutely no analysis...more bandwidth isnt nescessary because as a beginner you wont know enough to be able to make or troubleshoot anything that uses signals above 1 MHZ since it starts to get into i need more knowledge teritory , and the few critical math functions will allow you to better visualise signals and how they act upon each other, triggers are standard ...learn how to use it and try not to destroy the inputs with high voltage

>> No.1904258

i dont use a laptop. i got a tower. i dont use apple products. never have. its funny because i got a virus in a download 1 time that installed a fake itunes store folder

>> No.1904259

there are tons of projects like that that people went
>>bruh why is this so expensive i can make it for cheaper
but when you get into it you realise its not that simple or that the costs of those parts are not even that cheap as you thought , also everyone forgets about the fact that many products are very expensive because of the package form factor they are shoved in...i guarantee my left nut you cant draw that in a EDA program while being functional let alone make that thing to fit in the same receptacle with personally sourced parts to have the same functionality...also going from a through hole capacitor of 45uF to 2010 and 0805 smd package changes the price of a single piece from 0.08 dollars to 1 dollar per piece
debugging the software and testing the functionality is also included in the cost of the product and will be deducted from your and your friends time

if you can make the same thing for less money then man props to you , open a business and keep on doing it because thats amazing ...but i highly doubt it

>> No.1904260

when you start doing stuff at 50MHZ or more

>> No.1904286

I'm talking specifically about the thing that I drew a white square around, which is also what's in the picture on the right. That's what I'm trying to understand, not the rest of the electron gun.

>> No.1904302
File: 40 KB, 900x623, apu.png [View same] [iqdb] [saucenao] [google] [report]

programming isnt fun
i dont even know how to start off

>> No.1904303

well first I'd go to a thread that's about programming instead of resistors and capacitors

>> No.1904304

hot take: either start with microcontroller assembly or start with browser javascript.

>> No.1904312

assembly is fun
algorithms are fun
gluing together libraries is shitty and awful

>> No.1904315

>not coding your own libraries

>> No.1904316

>not posting from a computer that you built in a cave with absolutely no knowledge of modern technology

>> No.1904318

fuck you i'm typing this on my rockputer right now

>> No.1904325

its called a final anode of the electron gun and it gets connected to the screen assembly ..the voltage at the final anode determines the speed of the electrons by accelerating them with voltages of 25kV or more...yours seems to be missing the silicone insulation

also you could have found that out by googling (like almost 99% of shit in these threads) what is the dangly thing on a crt electron gun

>> No.1904327

>final anode
so basically it's used when the electron gun gattais with the tube and activates super galactic giga tube breaker?

>> No.1904329

if you are programming MCU-s then all you need to know is how digital logic works and just find out what commands are what equivalent for the language you are writing in (if, for , while , more than less than, not and basic arithmetic) if you cant do that then you are not intelligent enough to do any electronics anyways....if you mean programming applications then you need to learn how software is made, what are layers, classes, lists, databases etc and do the same as before in the laanguage of your choice

best thing to do to learn digital programming and low level GUI (like lcds or touch screens) is literally to get an arduino and do the test projects they give you and try to understand why and how does it function (by using books and literature to find out how digital circuits work) and then go up from there

>> No.1904330

made me chukle not gonna lie so heres your (you)

>> No.1904336

The heating element works fine on mine, it's like you say the stupid control box fails. Seems like there should be some way to just turn the heating element on without all the digital stuff, but I don't know shit about electronics.

I should probably just build a proper smokehouse too or at least a good pit bbq.

>> No.1904362
File: 9 KB, 800x400, Untitled.png [View same] [iqdb] [saucenao] [google] [report]

Hm, im still not getting any dc voltage from this.
48v ac from both sides of the diode.

>> No.1904364

im having trouble with finding the right registers in the datasheet, understanding them and using the correct syntax
i am reading through some older attiny datasheets i realized that the registers are straightforward and they dont contain as much seemingly useless crap

>> No.1904369
File: 282 KB, 1206x682, 20200907_193513.jpg [View same] [iqdb] [saucenao] [google] [report]

Pic related. The one above the RAY GUN is the final anode. The one below the Final anode is the electron gun.
Are these things connected by some sort of internal glass coating of the tube? because the final anode is not the same as that thing coming out of the electron gun. And I found about this specific thing nowhere on the internet, never seen an electron gun drawing that included this metal thing that is clearly coming out of the electron gun and is not the final anode itself (note: even inside the glass tube they are pretty distant from each other).

>> No.1904376

that's altium. i'm not sure what the correct way to do castellations is, this is just what oshpark will accept.

>> No.1904388

what are you using to program the MCU-s? I use Atmel AVR studio and i basically dont need to set registers by hand 80% of the time ...but otherwise it sounds more like you have problems reading datasheets and finding appropriate information in them

>> No.1904391

what do you mean by
>48v ac from both sides of the diode.

do you mean on the diode bridge there is 48V AC or before it

>> No.1904396
File: 1.40 MB, 4640x3472, IMG_20200907_204742.jpg [View same] [iqdb] [saucenao] [google] [report]

yeah bro now tell me if im gonna fry my lm317 and dps3005 modules when i plug them into this

>> No.1904406

sorry dude my bad ..i havent opened a crt in ages ...the final anode is on the transformer...it looks like its some grounding point on the contacting springs ...i guess it has no real purpose but i seen some indian talking about it in some video if yo uspeak the language

>> No.1904408

I bought an attiny 817 dev board
I am playing around with atmel start to set up things but I don't really know what I'm doing
I should probably stick to basedduino

>> No.1904410

where is your negative lead anon

>> No.1904411

considering that LM317 has a maximum input voltage of 37V then you will fry it regardless of the voltage being AC or DC....also i would most likely say your chinkshit multimeter is falsely reporting AC because of ripple or some shit like that, only way to be sure is to connect an oscilloscope to see the waveform

>> No.1904412

you should get a book about microcontrollers or some literature that will help you understand what you are looking at ....or just google everything you dont understand what it is untill you know what everything in the datasheet means ...it will help you tons in understanding what you are reading and therefore make it easier to find stuff when you know where you are supposed to look ....also an arduino is not bad for begginers and should be used as a learning tool , but its very limiting once you hit a certain threshold

>> No.1904414

on the socket ground
ok, though the transformer's a center tapped 2x15v which i thought was suitable

>> No.1904416

please connect your negative multimeter probe to the other end of the resistor

>> No.1904417
File: 342 KB, 1881x1120, lainscope.jpg [View same] [iqdb] [saucenao] [google] [report]

rectifryer is recifried.

>> No.1904419

fuck i want a lainscope

>> No.1904422
File: 777 KB, 1792x2775, 20200829_140703.jpg [View same] [iqdb] [saucenao] [google] [report]

I have identified all 8 pins of the electron gun, I just don't understand how to make it properly work (even just emitting electrons without accelerating them). If I input 6.3V at 600mA in the heater pins the heater should work, but what are the Red, Green and blue pins for specifically?

>> No.1904424

>tfw no waifu that lives in my oscilloscope

>> No.1904425
File: 149 KB, 1920x1080, 1571825961242.jpg [View same] [iqdb] [saucenao] [google] [report]

What soldering station is this? Never seen tips like this before... this is not T12, right?

>> No.1904427

Then i get 0 voltage in either ac or dc.

>> No.1904429

anon i think in order to help you we need to be extremely specific. you should have that resistor connected across the positive and negative outputs of your supply. then you should connect your multimeter probes across the two resistor terminals and measure that voltage, being sure that the power supply is switched on. is that what you did?

>> No.1904431

do you have a name or any numbers on the electron tube like a serial number or something ...or theTV serial number ....otherwise finding a datasheet will be quite hard

>> No.1904433

Yeah, that's right. I still got 48v AC when i immediately moved the negative lead to the plug ground.

>> No.1904434

thats a JBC soldering iron ..probably a t245 and a high power tip of some sort...all of that can be bought seperately , and there are even DIY versions of soldering stations with that iron ..without a more detailed setup picture there is no more to be told unfortunately

>> No.1904435

okay when you say "plug ground" i think mains earth, which would give you a completely arbitrary AC voltage across an isolation barrier.

>> No.1904436

I did try looking up both the TV and the electron tube (made by different brands) but I couldn't find anything.
The entire TV is a SINUDYNE model No. 14D00 and the electron tube is an ORION A34JXV70X73 (under this there is also the number "0204481").

>> No.1904437

that means that your rectifier is fried and need a new one ....your ac voltage is getting shorted to ground through your capacitors thats why you get 0V when you measure the voltage drop on your resistor ...when you connect one lead to the ground and the other to only one leg of the resistor you are measuring the voltage drop on your capacitors....get a new rectifier ....when you do that also get another voltage regulator that can handle 50V input

>> No.1904440
File: 72 KB, 767x522, 1587696925716.png [View same] [iqdb] [saucenao] [google] [report]

damn! that handle alone is more expensive than my whole station. and these cartridges ain't cheap either.
thanks anon!

btw, is this shit that much better than T12?

>> No.1904445

>btw, is this shit that much better than T12?

maybe...its more about the fact if its worth the money ...but that depends on your usage and if you feel like your soldering iron is not good enough

i had some weller station for years and was happy untill it started giving me problems ...then i bought a pace soldering station for a lot of money, but it heats up better , holds temperature better and i use it constantly , but i earn a living off of it so spending a few hundered dollars was worth it and it paid itself off in a month....so basically if your iron is good enough and you dont earn money off of it then no i dont think its worth it...and jes JBC is a premium brand for irons so its usually very good

>> No.1904472

holy based

>place 0201 on pcb
>turn on extractor fan

>btw, is this shit that much better than T12
Well for starters it's got a thermocouple that isn't in series with its element IIRC.

>> No.1904481

>but i earn a living off of it so spending a few hundered dollars was worth it and it paid itself off in a month
excellent point. I definitely agree with this. If I was making money with a soldering iron, I'd buy the best there is and wouldn't worry about the price too much.
>>turn on extractor fan
btw, that pic is from a YT video of a guy that repairs SD cards and shit like that. he's really good with that thing and can fix shit other shops can't. I guess it's worth it for him to have a station like that.

>> No.1904483

>SD cards
>If I was making money with a soldering iron, I'd buy the best there is and wouldn't worry about the price too much.
Fuck man I WISH I was in that position.

>> No.1904487

even under magnification, SD cards and flash drive components are super-small. and it seems that you need to know how to work with BGA stuff since almost everything's using them.
and you need a shit-ton of proprietary software that ain't cheap (probably around $5-10k).

I was looking to get into that biz but gave up because of cost.

>> No.1904489

Why can't the chinks copy the PC3000 and sell it for $7?

>> No.1904500

chinks suck at software. plus PC3000 is a massive piece of software and they've clearly spent decades on reverse engineering all the controllers.
I can't even imagine if some other company would be able to fund themselves trying to replicate some of the work. I'm guessing it's possible for someone to come around and concentrate only on the newest stuff and provide support for that.... but even then it will be a hard sell since these recovery shops will need support for old stuff too.
I believe the license is around $6,000 when I looked at this about a year ago or so. Plus you'll need updates and adapters for new shit that's constantly coming out.

I guess one way to get into this biz would be to buy a shop from someone else who's retiring or someting.

>> No.1904502

i mean if you are an EE engineer then all you need to do is open a business and go around and ask if someone needs a repair guy or if someone needs a to order electronic device...i make most of my money by making "your speed is <speed> " LED signs and solar battery chargers with built in blinker circuits for hazard lights on pedestrian crossings ..all of that are basic and rudimentary circuits but i make them by order so i can optimise them for each use case or i fix stuff for small firms that cant pay full support for very expensive machinery (for instance controller circuits for tire balancers or a spray feed controller for road marking machines)...and i fix stuff on the side for "friends", gigging bands etc .....basically the hardest part is finding people to work with/for because most of the time you deal with goverment administrations , governers , city planers etc , so its a lot of bullshitting , fancy dinners and broken promises...otherwise its pretty straightforward

>> No.1904508

>go around and ask if someone needs a repair guy
i've been worried that you'll just get cunts asking you to repair their cracked phone screen

>> No.1904515

i meant ask around at sme companies or people you know are in some industry that has electrical machinery ....but fixing screens is a start too anyways ...especially if you are business savy you can make a living off of that or have that be a stepping stone ...the first job i ever did bought me my first oscilloscope , another bought me a voltage refference , another bought me a high quality set of cutters, pliers , screwdrivers etc...after 10 years i have a full blown lab and many very expensive equipment but i invested most into the business and live relatively modest because i played it safe and didnt make many or big risks where i might have been much more wealthy now but i preffered to play it for the long run...you dont nescesarily need to become elon musk overnight

>> No.1904519

Y'all are pretty cringe for salivating over Lain but not remarking on the fact that it's a Russian scope

>> No.1904520


>> No.1904521

have sex

>> No.1904522


>> No.1904523

s e e t h e

>> No.1904524


>> No.1904525
File: 142 KB, 387x479, 1234123412341324.png [View same] [iqdb] [saucenao] [google] [report]

>Deus Ex: Human Revolution

>> No.1904526
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>> No.1904527


>> No.1904528

rent free

>> No.1904529
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>> No.1904532
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>> No.1904533

I thought this was a general of intellectuals

>> No.1904537
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>> No.1904541

Just thought of something lads: an /ohm/let is someone who posts in /ohm/. It makes double sense because EEs are the quintessential eggheads.

>> No.1904544

/ohm/ is an omelette that's been injected with an autism vaccine and dropped on the floor a few times

>> No.1904547

half of the people here are monkey brained and monkey trained and other half are stupid enough to waste time talking to glorified monkeys ...idk what you expected to find on a mongolian basket weaving forum

>> No.1904550
File: 1.73 MB, 266x473, 1542609903025.gif [View same] [iqdb] [saucenao] [google] [report]

You're the smartest.

>> No.1904556
File: 494 KB, 200x200, mind blowing.gif [View same] [iqdb] [saucenao] [google] [report]

>an /ohm/let

>> No.1904558
File: 128 KB, 949x1024, 1570590409482.jpg [View same] [iqdb] [saucenao] [google] [report]


>> No.1904559

i didnt say im smart nor smarter ...im talking to monkeys after all i just realise my surroundings

>> No.1904563

imagine the smell
Why do you have monkeys in your house?

>> No.1904566

That's called a stub, and for high speed signals they are bad because they act as antennas and wreck your impedance matching. If this was PCIe or HDMI or something that would be a definite no no, but I'm not sure if it could give you problems with USB 2.0 or not since it is quite a bit slower. You might try cutting the lines to the pins you aren't using with a razor blade. The proper way to do that would be to have 0 ohm resistors or solder bridges to each option and only populate one of them so the other side is disconnected.

>> No.1904600

>stick fork in wall outlet
>become a fried /ohm/let

>> No.1904603
File: 14 KB, 220x278, 220px-Egghead_from_Batman_66.jpg [View same] [iqdb] [saucenao] [google] [report]

Why yes, I do design and build my own MOSFET op-amps. How could you tell?

>> No.1904604

>if you are an EE engineer
I have no such qualification, though I dare say I’ve at least 80% the knowledge of an EE graduate. If I’d actually gotten into EE in the first place I doubt I’d be having trouble to this extent. Also I don’t have a driver’s license so I couldn’t do any of that on-site consumer repair work. For now I’m applying to local assembly jobs to see if I can get my foot in the door of the field that way.
If I had decent PCB work holding and a hot air setup I’d strongly consider advertising repair services on Facebook marketplace, but I don’t have the room for that at the moment. Reflow oven might be useful too.

>> No.1904608
File: 199 KB, 1202x1600, Egghead.jpg [View same] [iqdb] [saucenao] [google] [report]

Or perhaps I'll use BJTs this time!

>> No.1904621

can someone explain why we need to ground cases of electronics?

>> No.1904624

Noise mitigation, safety, and to meet regulatory standards.

>> No.1904658

RF shit too. Ever hear what happened with the first TRS-80?

>> No.1904666

It wasn't called Trash-80 for no reason.

>> No.1904681
File: 43 KB, 1608x1733, circuit.png [View same] [iqdb] [saucenao] [google] [report]

Okay probably a basic question but here goes. Suppose the following circuit. On the other side of pins 8 & 9 is a sensor, and "To 74LS logic" means just that; the output of this sensor is an input to some TTL logic.

Now, in the schematic (from which this image is derived) there's the 62K resistor. In the hardware revision I have of the same circuit, it's 10K. What might dictate the resistor value here?

Also the 150 ohm resistor is the same between both. What might dictate that resistor's value?

>> No.1904684

depends on what the sensor is, neither of those resistors relate strongly to the 74 series ic.

>> No.1904686

Hm. So I'm guessing my hardware revision must just use a different sensor than the schematic?

>> No.1904687

not necessarily, resistor values can be completely arbitrary. plenty of applications could work with a pullup resistor (the 62k pictured) anywhere from 1k to 100k.

>> No.1904692

This. It’s likely a pull-up to an open-collector digital sensor that has seperate power pins, like an IR receiver, or any analog sensor module with an integrated open-collector comparator for threshold detection. Either way the resistor value doesn’t matter so long as the effective output impedance is much lower than the 7400 input impedance.
On the other hand, that 150R is more likely to be a current-limiting resistor to a higher power analog sensor, like a gas sensor, or some other sort of sensor where the signal output is also the power input.

Any context as to what the two sensors are?

>> No.1904701

>Any context as to what the two sensors are?
It's either a LED/photosensor pair or a microswitch used to detect the presence of a notch. I'm not entirely sure.

>> No.1904708

>Seems like there should be some way to just turn the heating element on

there is. you just need to provide a schematic, and we can tell you to wire point A to point B using a big ass switch.

>why ground cases of electronics?

so you dont fry Aunt Karen's pussy with your badly taped battery-replacement-supply for her vibrator.

>> No.1904710

would correspond to the 150R value if true. the resistor value would be chosen to set the nominal LED current. this value should be considered critical without knowing the sensor internals, but anywhere from 100R to 1k could be fine in most cases.

would fit with the pullup. the resistor value is not as critical here. the lower bound is set by the drive strength of the phototransistor: if the resistor value is too low, the tranny won't be able to pull the output voltage low enough to trigger the 74 series ic. if the value is too high, switching speed will be compromised (as applicable) and eventually component leakages will cause issues with not being able to pull the output voltage high enough to trigger the ic. these are only really considerations if the drive strength is low or the switching speed is relatively high. otherwise just about any resistor will do.

>> No.1904756

>I have junk, what do?
>shitcan it
Seriously? I've got tons of scrap TVs, PCBs, and various wiring and was hoping to take those apart to learn more about electronics and get some useful parts. Would you say that is not worth doing?

>> No.1904761

Meh. Get a project that uses that stuff. And go to college.

>> No.1904763
File: 258 KB, 1328x1737, 9ef39ee6b4f96352bfd37f51e70c1998-imagejpeg.jpg [View same] [iqdb] [saucenao] [google] [report]

My wife bought me a laptop for my gay web designing, but I just use it to remote access my home server while still be able to spend time with the kiddo.

>> No.1904787

Gonna ask a really basic question because I'm fucking stupid and all the explanations I'm finding online about transistors are somewhat vague and I think skim over this
I'm trying to simulate a circuit in LTspice. On one of my transistors, no current (0-20pA which I'm assuming means pretty much no current is flowing) is flowing into the collector, but like 6.5 mA are flowing into the base and out of the collector. I'm assuming this means that electrons are flowing from the base to the emitter. Is this supposed to happen?
I'm trying to get the transistor only turn on when there's a signal from both the collector and the base. Do I just use two transistors in series for an AND gate here? Is current usually supposed to always flow from base to emitter provided there's an appropriate voltage drop?

>> No.1904801


fuck you, idiot. do a drawing, not a blog post.
drawings dont require interpretation: they are truth distilled.

>> No.1904804
File: 19 KB, 577x528, 24ca564e49145062c89db3ac39b28dc7.png [View same] [iqdb] [saucenao] [google] [report]

It's a simple question.
Here, I'll condense what I said: in an NPN transistor should current ever flow from base to emitter without a signal from the collector?
What do you want me to draw? Here's a picture of a transistor, that's all you need.

>> No.1904805

It's more in reference to the "what do" part. If you bought some electronic junk that you don't know what to do with it, don't ask about it here. We get too many people doing that.

>no current is flowing into the collector
>6.5 mA are flowing into the base and out of the collector
Do you mean out of the emitter? You need some sort of higher voltage for the collector to draw current through. Without one, a BJT will just act like a diode from base to emitter, regardless of what the collector is doing. Look at the semiconductor arrangement of a BJT to see this.
Also google how to make transistor logic gates because you're doing it wrong. You're not supposed to put a signal into the collector.

He means a circuit diagram, with your connections to voltage sources and resistors shown. We all know what a fucking BJT is.

>> No.1904813
File: 52 KB, 717x526, obvious.jpg [View same] [iqdb] [saucenao] [google] [report]


when you do a drawing the answer becomes super obvious after 1/2 a second's worth of examination: Icc = 0.000mA

>> No.1904814

>>no current is flowing into the collector
>>6.5 mA are flowing into the base and out of the collector
>Do you mean out of the emitter?
>You need some sort of higher voltage for the collector to draw current through. Without one, a BJT will just act like a diode from base to emitter, regardless of what the collector is doing. Look at the semiconductor arrangement of a BJT to see this.
Thanks this is what I was asking.
>Also google how to make transistor logic gates because you're doing it wrong. You're not supposed to put a signal into the collector.
Picrel is an AND gate, right? If there's a signal from B but not A doesn't that mean a signal is carried to out despite A not being powered?
Is the point then that the signal flowing into the base of a transistor and out of the collector should be significantly smaller than the collector current?
How would I do that if I want to hook up an AND gate to the base of another transistor? If the current flowing out of one of the transistors is enough to power the base of that transistor wouldn't it be enough to power the base of another?
Let me know if none of this makes sense
>He means a circuit diagram, with your connections to voltage sources and resistors shown. We all know what a fucking BJT is.
I know what he was asking but the circuit itself isn't relevant.

>> No.1904815
File: 2 KB, 145x200, images.png [View same] [iqdb] [saucenao] [google] [report]

Here's picrel

>> No.1904816


if the lower transistor is on then the output is some DC voltage irrespective of top transistor. so its not an AND gate. google knows how to make a proper one if you care to look.

>> No.1904820
File: 100 KB, 4004x2574, revision1.png [View same] [iqdb] [saucenao] [google] [report]

finished my schematic any style tips or anything else. first schematic i ever made. took me a while confirming all the parts worked for what i needed.

>> No.1904822

Can you just link me to a proper AND gate?
There's a bunch I've found but a lot seem to have the same problem that one does.
What exactly do you consider a proper transistor AND gate?

>> No.1904824


looks like a bomb exploded and scattered the body parts around the screen. schematics tell a story, but this tells me nothing. not even, ''what does it fucking do?" not even a title to provide a hint.

rating: scrap it and start over from scratch. also, remember circuit flow is top-to-bottom, left-to-right. we're not Jews here.

>> No.1904826

>link me to a proper AND gate?

https://www.youtube.com/watch?v=sTu3LwpF6XI (around 5 min mark)

but you'll probably need to negate the output. the way he wired it, LOW is considered HIGH coz LOW is what turns on an LED.

>> No.1904828

lol that would be retarded i can just move parts around so its in that order

>> No.1904831


so do it. switches are inputs so belong on far left. LEDs are outputs so belong far right. the eeprom is a slave to the CPU so goes after it, not before. a battery should look like a battery, not two terminals. if J1 is a USB why dont those 3 letters appear next to it. schematics are exposures, not a collection of clues to a mystery.

>> No.1904839

I've seen a few designs similar to this that rely on transistor beta to keep the resultant voltage down, I think. Hardly ideal though, I'd rather use a diode AND gate. Or you know, solely use NAND and NOR gates because they're universal.
There might be a decent common-base topology though.

Also ensure you put resistors in proper locations, as using a circuit without them may cause unexpected smoke release.

>> No.1904884
File: 5 KB, 642x391, Screenshot_20200908_054904.png [View same] [iqdb] [saucenao] [google] [report]

NAND gate w/ inverted output.
You might be able to do what you did here >>1904815 with FETs, since the issue here is just a quirk of BJTs

>> No.1904955

Why would only one end of a potentiometer give me a reading? Would the manufacturer disconnect one end? And would this have an effect on the volume of my radio because I cant get the lower volumes on it anymore.

>> No.1904980

a potentiometer with only two terminals is called a rheostat.
if it's supposed to be a potentiometer and one of the terminals is high impedance to the other two, it's probably broken. Usually a volume knob will have output on the wiper and input and ground on the other two terminals, so if the ground terminal comes disconnected internally it will be full volume all the time.

>> No.1904989

Right, but it's probably just a rheostat right? as the volume does adjust just not very much.

>> No.1904990

Have you tried to reflow the solder joints around each leg of the pot?

>> No.1905043

What's a decent online circuit simulator? I find quite a few with google, but what's a good one worth learning to use properly

>> No.1905047

Noob here, can anyone explain how this circuit https://www.instructables.com/id/Li-Ion-battery-level-indicator/ manages to indicate a battery charge when I would have thought it would be like comparing its own voltage to itself?

>> No.1905058

LED1 behaves as a very jenky shunt regulator, so the anode which connects to the series of resistors is a more or less constant voltage.

>> No.1905092

Would a zener diode be a better shunt? What value zener diode would you substitute if you were making the circuit?

>> No.1905126

Are there any suppliers of new manufacture CRT tubes as components?

>> No.1905137
File: 107 KB, 1077x617, shiftregisters.png [View same] [iqdb] [saucenao] [google] [report]

Is anything glaringly wrong with the way I daisychained these shift registers? It's an LED chaser. Sorry for noob question

>> No.1905138

Thanks man, this works great.
Now I actually understand transistors
>since the issue here is just a quirk of BJTs
Just to be clear, FETS don't run current from the base to the emitter, only from collector to emitter?

>> No.1905140

>Would a zener diode be a better shunt?
yes. Note this from the instructions:
>When this circuit was simulated on LTSpice, I used R1 value 18k, however, after this circuit was soldered on a printBoard, this value was to high, so i had to change it to 15k
I'd say there's a pretty good chance that was due to variability among LEDs, they don't all take the same voltage even if the color is similar.
>What value zener diode would you substitute if you were making the circuit?
Somewhere between 1.6 and 2.0 volts to replace a red LED. If you want the exact value they are expecting you can calculate it with ohm's law. Or you can pick a value and recalculate the R1 R2 voltage divider.

>> No.1905144

BJT is two diodes where the second diode is defective until you put current through the first one.
FET is a resistor and a capacitor where the resistor value depends on the voltage you put on the capacitor.
Autists will sperg at you for using base/collector/emitter terminology to talk about FETs.

>> No.1905148

Alright thanks
I honestly haven't looked into FETS at all but I really should've by now

>> No.1905151

>Autists will sperg at you for using base/collector/emitter terminology to talk about FETs.
kek I was about to until I read this

>> No.1905191

i have
a 1 mega hertz crystal oscilattor
a op amp
access to transistors, capacitors and resistors
do you have any guides for building transmitters with these in analogue?

>> No.1905276

Simplest method would be to send OOK (on-off-keying) at 1MHz just by toggling the oscillator (Schmitt inverter across crystal), with some low-pass filtering to shape the square wave a little better and a class-A (or B or AB) amplifier. With this you could send Morse code or other digital information. A little more finesse could be applied to shape the keying strokes for less nasty harmonics.

But whether you’ve a right to legally transmit at 1MHz (or 500k or 250k or whatever) is another issue altogether. If you want to tune to a different frequency with the 1MHz as a reference, I can only recommend building a phase-locked-loop with some (adjustable) clock dividers in there. Bonus points for using a sinusoidal VCO so you no longer need those filters. Ditching the 1M crystal entirely for a more adjustable oscillator topology is an option, but it might have less stability than you’re comfortable with. With a mixer (or some other voltage controlled amplifier circuit) you’d be able to transmit AM radio, and I think you can use extra dividers in a PLL to enable you to transmit FM or FSK or whatever. Might be able to send a couple different symbols of ASK with just a little resistor ladder magic after your crystal.

>> No.1905293

looks good to me. you should throw a ceramic cap on your power rail too.


>> No.1905348

Since PICs still seem to be in use and the MCUs themselves aren’t that expensive, what’s the best way to get into using them? Do I need a pickit for programming, or can I use a USB-serial bridge?

>> No.1905424
File: 40 KB, 469x142, Screen Shot 2020-08-13 at 11.12.47 PM.png [View same] [iqdb] [saucenao] [google] [report]

first-timer here, I have pic related (a PSU) breadboarded and was planning on soldering a power cord to the AC transformer so I can check to see if my breadboard works as intended. My problem is that I don't have any solder, and don't know what kind to buy. I have strip board as well and I'd like to eventually be soldering my breadboard projects onto the strip board, so I'd like solder that works for that as well. Totally willing to buy two rolls of solder if necassary though, I just want to move the project forward.

Thanks in advance

>> No.1905428
File: 191 KB, 1513x937, if it's kester, it's good.jpg [View same] [iqdb] [saucenao] [google] [report]


Kester makes a bunch of diff ones, this is probably the one they sell the most. you want ...
- rosin core
- sn63pb26 (63% tin, 26% lead)
- thin, like 0.8mm diameter
- either the model 44 or 245, or 285, or whatever, but always with the above characteristics

>> No.1905432

I don't like that the spool is hidden, hopefully I'm getting enough to last a while here..?

What's the diff between 44, 245 and 285?

>> No.1905436

I just buy whatever garbage the local jaycar has, works good enough for me.

>> No.1905438

I don't know if Lowe's is a Jaycar, but what they had felt suspicisouly overpriced and looked really thick for my purposes

>> No.1905442

if you recommend pullng the trigger after reading >>1905432, just lmk and I'll buy the 44. I'll probably just buy it anyway actually

>> No.1905443

Might only have plumbing solder. Plumbing solder (or any lead-free solder really) can't have lead in it so it's made of silver and tin and neither of those are cheap. My lead-free solder was just tin and copper, but it was like 99% tin. Felt the same as cheap 60/40, but what do I know?

>> No.1905444
File: 496 KB, 643x580, 1587597627390.png [View same] [iqdb] [saucenao] [google] [report]

How am I supposed to hold SMD diodes in place effectively? I'm using tweezers, iron at 350C, flux, the whole deal. The fucking diode keeps slipping, and my solder isn't flowing. Should I just goop on more solder?

>> No.1905448

>What's the diff between 44, 245 and 285?

44 is standard, 245 is low-residue (easy cleanup) and 285 uses a super-duper flux. as for size, i'm not sure, but i believe they're 500 grams, which typically lasts 20 years of occasional use.

>> No.1905449

Lowe's is not Jaycar and you're very unlikely to find suitable solder there. I think Jaycar is more like what Radio Shack used to be like.

>> No.1905451

>500 grams

digikey says they're 454 g (a cubit in Americanese)

>> No.1905452

>my solder isn't flowing
More flux? What tip geometry do you have? If the thermal resistance from the tip to the joint is too high then you're gonna be taking more time to heat up the PCB enough for solder to flow on it.

>I think Jaycar is more like what Radio Shack used to be like
This, but more expensive. $50 for an arduino and nothing else, can you believe it?

>> No.1905478
File: 1.75 MB, 4032x1908, 1585964329618.jpg [View same] [iqdb] [saucenao] [google] [report]

Flux has helped a bit, though I'm finding using nearby through-holes as a way to hold the solder is helping me form bridges of sorts. Do these look okay? May seem like a lot (or just right?), but it has worked to get these things on there. One is a bit crooked (second from the top), but it's seemingly secure.
>What tip geometry do you have?
D-25 tip on a TS80. Flat-head. It's thin and tiny, so still acceptably easy to control in this case.

>> No.1905483
File: 385 KB, 516x358, Clean-Concave-Solder-Joint.png [View same] [iqdb] [saucenao] [google] [report]


solder shouldnt look like that, ever. it should be all shiny and chrome. so it can enter Valhalla.
maybe reading might help: https://www.seeedstudio.com/blog/2019/08/07/13-common-pcb-soldering-problems-to-avoid/

>> No.1905484

raise the temp. solder should flow, not ball up

>> No.1905486

I'm aware of this, but even at high temps, my solder is rarely so shiny. Just about always goes dull in appearance. I don't think I bought lead-free solder, though. I think my flux may be shit. It's knock-off RMA-223 from China. So thick.
I don't want to kill my components. I'm already working at 350C. I can go as high as 400C, but that is untenable. Especially if I start working with LEDs.

>> No.1905498

I think your temperature is too low. Your solder beads are lumpy, as if they were melted and solidified at different times. There's plenty of flux from what I can see. If your iron is set to 350C, it might just be that your thermocouple isn't accurate, or that your thermal resistance is too high.

>I don't want to kill my components
If your solder joints look like that, then your PCB certainly isn't getting hot enough. If you get in and out in a normal speed then you're not any more likely to burn parts, since the PCB never gets near your thermocouple's temperature anyhow.

I don't think your flux is bad quality, it's covering the joint but it's still dull looking. It could definitely be a bad solder alloy, so I'd do some tests on shitty perfboard or whatever first.

>> No.1905542

in consumer appliances cases are grounded for protection...if you have a bad circuit or failing insulation on high voltage cabling you can get an electric shock hazard...you ground the case so if that happens the current goes through the case to the ground and either popping a breaker , or just diverting enough current so it does not kill you and just gives you a mild shock

otherwise it gives good RF shielding from EM that are either present or made by the device , also static electricity shorts through the case instead of through the components

>> No.1905543
File: 18 KB, 523x226, Screenshot_2.jpg [View same] [iqdb] [saucenao] [google] [report]

the 150 ohm resistor is just there to limit current through the sensor and is governed by the voltage and current limit of the sensor

the 62k resistor is a pull up resistor for the ttl logic drive and is also basically there to limit current into the 74 IC , pic rel is a formula to pic resistor values for pull ups ...it will mostly depend on the IC type and maximum current written in the datasheet....basically 10k is most of the time enough especially with newer ICs that are more robust

>> No.1905546

learning how other things work and reverse engineering them is not a begginer level thng ...electronics is one of those things that require both theoretical and practical knowledge which you get by first STUDYING then doing practical tests to see physically see what you studied (studying does not nescesarily mean going to school/college because you can find literature on it everywhere but it makes it milion times easier to understand)...you are better off finding some textbooks about basics of electricity and magnetism and getting a handful of transistors, resistors, caps and inductors and a multimeter and playing around with those ...then graduating to an arduino to learn a bit more about digital systems then doing some personal projects with first discrete parts then doing the same thing with IC-s

>Would you say that is not worth doing?
tl;dr no its not
at least not in that way

>> No.1905552

google how a BJT transistor works (on the semiconductor barrier level)

yes if you energise the base of BJT transistor it will leak out through the emiter since the barrier will be polarised in a way that cunducts electricity ....you need to add a voltage source to the collector for it to sink a current through the positively polarised BE barrier

>> No.1905556
File: 170 KB, 1342x558, Screenshot_3.jpg [View same] [iqdb] [saucenao] [google] [report]


the anon that replied to you was rude but correct ...there should be a method to the madness and most of the time chematics should either flow from left to right or from the center outward..but you should be able to follow the current path linearly without having to jump around the chematic everytime you look for something

also there is too much unnescesary linking in the schematic, half of these things you can just connect directly...or if you really like doing everything in blocks then do a hierachical schematic (block schematic) where you put each aprt in its own rectangle with the output and input pins displayet at the edges

>> No.1905560

your potentiometer/rheostat has its wiper is either dirty or its worn out and does not have its rated resistance anymore ...put a new one in they are like 30 cents

>> No.1905562

get LTSpice its free small its tried and tested with a big libray of real world parts, also it has a big range of analysis tools

>> No.1905563

between Vcc and GND pins should be a decoupling capacitor of 100nF or 10nF for every digital IC you use for the rest of your life

>> No.1905564

get the cheapest programmer you can that works for your programming environment that supports the PIC you want to use...there is no standard for hobbyists ..everyone uses what they can since programmers are expensive

>> No.1905566

you can use any kind of solder basically ...make sure it has flux in it (it will say on the package) and its rated for the temps you will be using it for since SMD and through hole and general purpose things are done at different temperatures (300-350 is for you) also more expensive solder is usually better but whatever you buy if its in a roll it will last you a long time (i have a roll of solder that i paid 100€ for and i have been using it for like 5 years and i solder for a living)

>> No.1905570

you basically shouldnt hold any SMD component while soldering ...the thermal mass of your tweezers is larger than the component thermal mass so your component is seeping its temp to the tweezer ....also you should keep in mind the angle of the tip to the board and how much coverage you get ...basically you are trying to warm up the board and pads first , the component is small enough that it will heat up by being close enough...also flux is your friend and lover there is no such thing as too much lube and there is nos uch thing as too much solder ...also greasy or otherwise dirty and corroded pads will have a hard time accepting solder to them

>> No.1905573

I have never seen a satisfactory explanation for how any semiconductor device works.
"And then all the electrons stopped going to the N region because the holes in the N region started putting up yard signs and everybody says they don't tolerate minority carriers in their neighborhood"

>> No.1905584

my chinese pickit ("kit 3.5") has worked well on the dozen or so pic variants i've tried, and it probably cost under $10.

>> No.1905588
File: 15 KB, 512x253, BJT VI curves.gif [View same] [iqdb] [saucenao] [google] [report]

>how any semiconductor device works.

yeah, it's all gibberish. but if you look at the VI curves, then that's the real deal. if you apply V voltage, then I current will flow. the curves characterize how the device will act in real circuits, irrespective of the arcane internal machinations.

>> No.1905589

then you either didnt search for more sources of explanations or you are not intelligent enough to understand it

silicon by itself in a pure undoped form has no free electrons and therefore isnt naturally conductive (not a good insulator but its an insulator)

you have two types of doped crystals ..one that has aditional free ectrons(higher valence level) one that has a deficit(lower valence lever) ...when you take the two types of silicon crystals and connect them the difference in free electrons causes a voltage potential and causes a current of electrons into the "empty spaces" because chemistry shows that non balanced valence levels will cause a reaction called electron combination ...that means that the free electrons will go to the place of lower valence and recombine

by recombining you get a pure undoped piece of silicon that again becomes an insulator...once the barrier of insulation becomes big enough that free electrons dont see free valence levels you stop doing recombination and the growing of the insulatin part stops

since you have a piece of silicon that has more electrons and one with fewer you get a voltage difference between them with a non connductive barrier

by applying a backwards voltage (non conductive) you cause (+battery to - crystal and -battery to + crystal) you cause a bigger barrier between the crystals because the battery pulls the opposite charges to itself

by applying forwards voltage (conductive) you basically force the electrons iin the barrier out of their valence bonds (because quantum mechanics and electronvolt energy levels) and make free electrons again and cause recombination to start up again...since there are more electrons now than "holes" you get constant free electron generation and the thing becomes conductive

once you remove the voltage free electron generation stops and then the whole thing recombines once again with a non conductive barrier

>> No.1905591

>doped crystals
can you smoke it?

>> No.1905592
File: 22 KB, 1023x532, Chip-smoking.jpg [View same] [iqdb] [saucenao] [google] [report]

yes, actually

>> No.1905593

chinkshit iron? Try "375"
for large parts you'll need to crank it up to "425" or so

>> No.1905594

some of the gasses involved in creating the crystals could get you high i think

>> No.1905597

They don't call it "magic smoke" for nothing

>> No.1905598

>bro you want some 317?
>this is the good shit, straight from ebay

>> No.1905609
File: 77 KB, 457x599, Screenshot_4.jpg [View same] [iqdb] [saucenao] [google] [report]


i got some teasing nudes for that smoking hot piece of chip

>> No.1905617

based coomer

>> No.1905619




>> No.1905661

>op a
thanks a lot man. really detailed.

>> No.1905728

>I think your temperature is too low.
At 350C? At 380C? I'm finding that pressing into the solder mass with some force helps heat it in, but as a result, I have a hard time spacing the component into the solder.
>It could definitely be a bad solder alloy
I think it may be. I made a joint or two that was shinier than the others, but replicating it has been difficult. It's perhaps more likely that I'm just inexperienced. I don't even care if my results are perfect, just that they're decent and functional.
>basically you are trying to warm up the board and pads first , the component is small enough that it will heat up by being close enough
I tried to warm up the pad with some solder first, but the solder solidified far too easily each time, so I had trouble pushing in the component on even one side.I
>you basically shouldnt hold any SMD component while soldering
How am I supposed to keep it into the pad at all, then? Besides solder glue, which I do not have. Maybe I should use better tweezers that aren't so fine and smooth?
>also flux is your friend and lover there is no such thing as too much lube
My flux has been horrible to clean. 70% isopropyl barely does anything to clear it, and it just leaves too much material behind.
TS80. Goes up to 400C. I tried 380C before, which melted things more effectively, but still didn't afford me an easy passage to placing the component in. I noticed if I put some force into the solder mass, I was able to melt it more easily. That hasn't performed well for actually bonding the components onto the pads, though. Takes too much space, and is still difficult to slip in.

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