madbeanpedals::forum

Projects => General Questions => Topic started by: Guava on March 18, 2017, 04:11:02 PM

Title: Transistor Tester 10K Trimmer (and DC Jack wiring?)
Post by: Guava on March 18, 2017, 04:11:02 PM
I'm attempting to build a transistor tester for a few germaniums I've picked up (going to etch the pictured board).  I don't have any 5K trimmers for the 2.472K, but I have a 10K trimmer.  Would this allow me to get to that setting or would it be too wide of a range?
Title: Re: Transistor Tester 10K Trimmer?
Post by: 287m on March 18, 2017, 05:35:14 PM
Quote from: Guava on March 18, 2017, 04:11:02 PM
I'm attempting to build a transistor tester for a few germaniums I've picked up (going to etch the pictured board).  I don't have any 5K trimmers for the 2.472K, but I have a 10K trimmer.  Would this allow me to get to that setting or would it be too wide of a range?
short, yes you can use 10K trimpots
i usually use perf below, because not have trimmer
(https://4.bp.blogspot.com/-EWCmT0awml0/WM1uft8dqsI/AAAAAAAAAT0/u6Nj2BTJa-McvDfji_XmkTdI5spYNY1VACLcB/s1600/tr-tester.png)
R2 + R3 in parallel get aproximate 2K481. just lucky got near 2K47
just socketed for transistor and power, so i can use for npn or pnp. although never testing pnp. haha
Title: Re: Transistor Tester 10K Trimmer?
Post by: Guava on March 18, 2017, 06:35:36 PM
Cool, thanks!  Also, if I'm using the board I posted, can I leave out the polarity switch if I run the DC Jack +9v to A and Ground to B?
Title: Re: Transistor Tester 10K Trimmer (and DC Jack wiring?)
Post by: Guava on March 19, 2017, 04:54:02 PM
Trying to learn to read schematics and answer these most likely very simple questions on my own, but don't want to ruin a transistor to find out  :o

If I'm testing PNP germaniums and leaving the polarity switch off of this board and just wiring a D.C. Jack, I would run the +9V to the emitter, correct? (I'm going off of RG Keen's schematic).

Thanks for any help!