Swapping capacitors.

Started by supernaut, July 04, 2009, 01:31:25 AM

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supernaut

I went and bought some capacitors today for this build http://www.geocities.com/j4_student/voxtreb.jpg and when I saw the size of the MKT .47uf cap I decided to go with the more compact electrolytic one. I just need to know what way do I solder it in due to it not being bi-polar?

BAARON

Negative terminal attaches to the volume pot, positive side goes to the transistor.
B. Aaron Ennis
If somebody makes a mistake, help them understand what went wrong.  Show them how to do it right.  Be helpful.  Don't just say "you're wrong, moron."

supernaut

Okay thanks. So how do you work it out? Because that is the opposite to the 10uf one.

R.G.

Quote from: supernaut on July 04, 2009, 04:12:43 AM
Okay thanks. So how do you work it out? Because that is the opposite to the 10uf one.
The capacitors are marked with a "+" and a "-" symbol. The way you work is out is that the pin with the "+" symbol always goes to the place in the circuit where the voltage is more positive.

It may be that you're missing the fact that the DC voltage at the top of the volume pot is zero. This is because the capacitor itself blocks all DC, and the volume pot then sucks the end of the capacitor connected to it down to zero volts. If that end is at zero, then the other end of the capacitor must be more positive, because wherever you connect it to the rest of the circuit, it's going to be more positive than ground; that's because the circuit is powered from 0V and +9V, so no place in it can be more negative than ground. Hence, the negative marked end goes to the volume pot.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

supernaut

Oh ok, thanks for the explanation. Also sorry to BAARON, I read your post wrong. Out of interest though, why is it 0 volts at the top of the volume pot?

R.G.

Quote from: supernaut on July 04, 2009, 09:41:47 PM
... Out of interest though, why is it 0 volts at the top of the volume pot?
Quote from: R.G. on July 04, 2009, 10:59:49 AM
... the DC voltage at the top of the volume pot is zero. This is because the capacitor itself blocks all DC, and the volume pot then sucks the end of the capacitor connected to it down to zero volts.
:icon_biggrin:
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

supernaut

Oh god I'm an idiot. I really am having an issue with reading posts arn't I haha.