NPN FF with PNP trans cap polarity

Started by m_charles, June 01, 2010, 07:55:52 PM

Previous topic - Next topic

m_charles

Hi, am building a FF PNP wired negative gnd. I have it all set, but want to use a 1uf on the OUT CAP (no, not the IN). The one I have is polarized. I know normally (if PNP) you'd keep the neg pointing in at the circuit, the pos going to the pot. But I'm a little confused about this when it comes to the NPN wiring "tricking" the circuit. My guess would be neg out because the neg ultimatley is what's heading to gnd via the 500K pot.
As far as the IN cap, I have seen a schem on GGG showing pos out neg in for this wiring, but RG has a NPN-PNP FF with neg out pos / in.
Any info is appreciated.  :)

PRR

You got it right.

When in doubt: build without the cap. Power-up. Stick your two voltmeter leads where the cap should go. When the meter says positive (not "-"), the red lead is on the Plus side.
  • SUPPORTER

m_charles

thanks. ended up socketing. It wants +pos facing in for in and out caps or there's lot's o' weirdness...

zombiwoof

#3
Wow, with that value isn't it going to be really bassy?.  Or are you making up for that by changing the input cap or some other change in the circuit?.

Also, wouldn't it be a better option to use one of those metal film 1uf caps?.  They're pretty compact, and no polarity issues.  Is the cap you are using an electrolytic?.

Al