Gristleizer Transistors

[tomas1808]

Hi,

I ordered two 2N3906 from Futurlec for my Gristleizer (one for the gristle and the other for the charge pump). Instead I got one 2n3906 and a 2N3904. From what I gathered one is NPN and the other PNP.

Are they the same? Does it work as a substitute? Different pinout?

Thanks!

[Taylor]

No, they are not interchangeable. As you found 2n3906 is PNP, 2n3904 is NPN.

They messed up. I would let them know, just so they know made a mistake. But since the part probably cost a couple of cents it's not worth having them send you a replacement  across the planet.

But, it's been a while since I looked at the Gristleizer, but looking at my schematic, there's no 2n3906 in the charge pump. My board does actually use a 2n3904 to flash the LED. Are you building this on your own or on the PCB I did? Can you post the schem from which you're working?

[tomas1808]

I am using the Gristle and the Bipolar 9V PS schematics from gaussmarkov.net. Here are the links:

http://gaussmarkov.net/wordpress/circuits/gristleizer/
http://gaussmarkov.net/wordpress/circuits/bipolar-9v-power-supply/

[Taylor]

Hmm. Well, you only need the transistor if you're using the input jack to turn off power (if you're using a battery). If you do want to use a battery you'll need to get a 2n3906 or substitute like 2N4250 or 2N4402

[tomas1808]

Problem solved. I just went to the nearest electronic store and bought a few 2N3906s.

Thanks for the help Taylor