NPN PNP problem!

Started by pixel, May 17, 2008, 03:36:53 PM

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pixel

I was making a silicon fuzz that called for some PNP transistors. Turns out I have NPN transistors! Oh the horror! Is there any way I can make my circuit work with the NPN transistors I have?

Seljer

if there are only PNP transistors if you turn around every polarized component it'll work the same with PNP transistors (so that is all diodes, polarized capacitors and the battery. that usually means you can't power it off a wallwart in conjunction with other pedals, or in the cases you can, strange things start happening)

pixel

wait, you mean it'll work the same with NPN transistors right?

oldrocker

#3
Yes but you have to reverse all of your polarized components.  As Seljer says that would mean the + and - on all components would be reversed.  Polarized caps, diodes (LED's), the battery anything that uses positive and negative leads will now be hooked up  opposite of what they would be if the PNP transistors were used.  Of course then you have to make sure the transistor pinouts of the NPN's you're now using are oriented correctly.
Some say there is a difference in sound between a positive grounded system and negative ground systems.  I have never heard a PNP Fuzz Face so I couldn't help with those differences.

petemoore

  You never want the negative '-' marked lead on your polarized capacitor to become more positive than the unmarked
  • lead.
      diodes follow, identified easily for discussion as shown marked on schematics, start with a schematic  for a standard, negative Gnd. Fuzz Face which calls for NPN transistors.
Convention creates following, following creates convention.

pixel

hey, thanks for the help everyone, i really appreciate it. i have a little problem though, how can i determine what the "e" "b" and "c" pinouts of my transistors are?

mdh

Google the part number and look for a datasheet.

earthtonesaudio

There are also about a bazillion npn fuzz face variations to point you in the right direction.  Look on muzique.com, geofex.com, and here: