/diy/ - Do It Yourself

>leave out the RA
no. look at the schematic.

You can use diodes to have separate charge/discharge paths/resisters. It will throw off the formulas a little (more so for a low supply voltage)
Try googleing duty cycle>50% or <50% (I don't remember which)

You could also run the ck out to a flip-flop to get perfectly equal high and low (50% duty cycle) at half the frequency

I thought I saved the schematic that someone posted last time this was asked, but I can't find it.

Here's this anyway. you might like it

Ah, I see now. I didn't think about the effect on the rest of the circuit taking it out would do. Just that math-wise it would balance out the formula. (I had a feeling that it was too simple to work that way)

Thanks for the idea on the flip-flop. From what I understand of them that's probably the route I want to take with it.

Welcome btw. I'd like to see more electronic enthusiasts here.

Word of advice though, Don't give your Email to 4chan. Bad things could happen.

>>386754

You were probably thinking this circuit.
There are other possibilities, too.

Ton=(R1 + part of R2)0.693C
Toff=(R3 + Part of R2)0.693C

I hope this helps anon, I was too lazy to make a proper simulation for the circuit and sence I don't have a scanner where I am right now I took a picture with my cell phone, sorry for the bad quality.

If you left out the resistor Ra, that would make Ra in the formula equal to infinity—if you want Ra=0 you'd need to replace the resistor with a short circuit (zero resistance).

(Of course then you'd overload the discharge transistor.)

For a flipflop you could use a 54'73 or 74'73 (I can't remember the differentce between the 54xx series and 74xx series any more. And a logic family to match what you're doing with the 555. HC or LS maybe.)

>>386758
Thanks for the advice. I've actually been here for quite a while, just never bothered to tripcode as I didn't have anything to actually share until now. It's exciting, motivation came from nowhere and I'm doing a lot of projects. Plan on writing an instructable on this one once I get it done. Making an all-in-one function generator and voltage source. Starting simple and increasing accuracy as I learn. Will probably have some more bells and whistles at the end of it but I was going for accuracy as I plan to experiment with signals and electromagnets later.

The email was made for giving out to people I want to contact on here but I forgot to take it back off since last time I did that. Don't want to lose it as I've actually grown attached to the name.

>>386756
I love animations like this. Helped me a lot when I was taking classes to understand the concepts.

>>386776
I think I'd get this more if I knew what R2 was. A three prong resistor? Just don't know the symbol.

>>386791
I think the flipflop is the route I'm going to take, just have to do some learning into their operation as I've forgotten. Thanks for the suggestions, I'll check out the datasheet after trying to find them in my textbook.

>>386827

r2 is a potentiometer. it has two leads on either end of a "track"; there is a knob or something that you turn, and a wiper moves along the track, so that the resistance from the wiper to either end of the track varies.

it is used to produce a variable resistance or a variable voltage, depending on connections. it is a very common item. google potentiometer

>>386833
Oh awesome, yeah. I used one of those in my voltage regulator and am familiar with the principal. I don't know why I didn't make the connection there as the symbol I'm familiar with has the arrow slashing through the resistor symbol rather than on the side.