/diy/ - Do It Yourself

>>482698
Then use the 1mm. The cells won't put out enough current to mess with a 1mm. The electrical resistance between 1mm and 1.5mm is nominal.

>>482695
Electrically there's no difference. Mechanically is another problem. Either get the right tabbing, or modify the existing tabbing or enclosure to make it fit. You're not soldering to the glass, you're soldering to the pads. You can have overhang without problems (except the output will be less because you're covering a part of the solar cell).

>>480895
It's going to be real difficult finding a jfet op-amp that will work in the 5V range (+-2.5V). You may want to switch to something bipolar, like the OPA1602 or OPA1604.

>>480139
You can rewind the secondary from a microwave oven transformer to get the 30A you need but at a few volts. Use multiple modified microwave transformer secondaries in series to get the required voltage. Add a high current bridge rectifier on the secondary and a variac on the primary for DC voltage control.

>>478710
Grab a resistor from you junk pile of spare resistors, and solder it to where the DC jack is soldered to the laptop board. I know you might not have a junkpile you can freely dig into, so you might have to order some resistors, or look around for some electronics your neighbors are throwing out to cannibalize some parts.

>>478703
I'm leaning heavily on a bad DC jack in the laptop. If it doesn't hold the plug tight, a weak connection might read good voltage, but will have enough resistance to cause the voltage to drop under load. Can you measure the DC voltage at the laptop jack with the adapter plugged in and supply a resistive load at where it plugs into the laptop? The laptop doesn't need to be on for this. a 100 ohm, 4 watt resistor shouldn't drop the voltage that you initially measured.

>>478699
Sorry. Caps is slang for capacitor. They're used to filter pulsating DC that comes from a rectified AC source into a steady, un-pulsating DC source. In switching power supplies (like your adapter) they're under a lot of stress.

>>478697
If the adapter can't supply the amps required, the voltage drops. Using voltage as a measurement is fine. I hope he's able to load the adapter properly with his tests.

>>478690
No. The voltage is fine. Most adapters for laptops can be off as much as + or - one volt. The voltage isn't a deal killer, although if it has bad caps in it, your voltmeter may not catch the excessive ripple. Normally the voltage drops a lot under load if the caps are bad.

>>478684
Was it dropped while plugged in?
Let me get this in here before I leave. It might be relevant for the future.
http://www.laptopjacks.com/

>>478675
Even if the solder points are good, you can still have damage to the springy parts inside a jack. If you have another working power supply that you can cut the plug off of, you can temporarily solder it directly to the solder points of the DC jack. This will bypass any problems the DC jack may have. If it still doesn't like to stay on, you're looking at bad semiconductors on the laptop main board.

>>478666
I'm leaning heavily towards a bad DC jack in the laptop. A loose or intermittent connection could cause the laptop to do this.

>>478631
The adapter for laptops can be off my as much as + or - one volt. Your adapter is fine as far as voltage is concerned. I assume you measured the voltage under a load (measured while plugged in). Have you checked the laptop fans? If the fans aren't moving, either overheat or fan sensing circuits will shut down the machine to protect it. Have you tried powering it up on AC but with the battery removed? If it doesn't power up, you might have a bad DC jack on the laptop, or the regulator circuitry in the laptop have gone bad.

>>477955
A single bipolar transistor oscillator may be reliable to start, but not efficient. I suggest a ZVS design with mosfets.
http://www.instructables.com/id/ZVS-Driver/step3/Schematics/

>>476889
Not keyring sized. More pocket sized:
http://www.ladyada.net/make/wavebubble/index.html

>>474760
8V positive regulator. Replacement equivalent MC78L08

>>475724
Have you thought about using brass bushings? To be honest, unless you rebuild it, you're just band aiding the problem. Also, you may want to see if there's a removable door after market mod. Might be less work.

>>471992
Personally I'd break the L/R lines going directly to the amp chip. Use a female stereo plug that also switches. When you plug a cable in, the plug disconnects the amp from the rest of the circuit.

>>470797
Check which side of the DC jack on the router has continuity to other system grounds (poke the antenna connector, any exposed shield)

>>469967
Before you crazy with this, I'm going to tell you something that sounds like a broken recor... err a skipping MP3. Replace all electrolytic capacitors. Tube TV's use a boost capacitor for the vert. It should be around 170V and 47uF. If your yoke were open or shorted, the x-ray protection circuit would shut it down. It would also help to know the make and model of the TV.

>>468666
To clear soldered holes, heat up the pad with a soldering iron and push a wooden toothpick into the hole. With the toothpick still in the hole, remove the iron. Remove toothpick after solder cools.

>>464776
Try this one.

>>461724
Velostat is a manufacturer of static dissipating material. Adafruit sells a variable resistor using it:
https://www.adafruit.com/products/1361
You may be more interested in this:
https://www.adafruit.com/products/166

If it's a steel ball, you can use an oscillator that uses a coil and a capacitor to set the frequency. Place the coil under where you want to sense it. When the ball rolls over the coil, it pulls the frequency.