[sdiy] Modern transistor matching

Tim Daugard daugard at sprintmail.com
Fri Mar 21 15:31:20 CET 2008

From: "Grant Richter" <grichter at asapnet.net>
> The last bag of 100 x 2N3904 transistors I got from Mouser, I sorted
> them by my usual method.
> All 100 tested +/- 1 mv. of each other at room temperature (all 100
> came out of bag matched to each other to Moog spec.)

I noticed the same thing the last time I tried to match transistors. I thought I was doing
something wrong. I went on and matched the transistors for gain (Hfe on my meter). I found
enough transistors that matched (with my finger heated method) that I have groups of two's
and four's that are matched for Hfe within the limits of my meter. This sorting resulted
in fall outs on either end of high gain and low gain transistors which went into my bins
for special purposes. The transistors are used when I need extremes of high and low gain.

Mine are from Mouser also.

Tim Daugard
AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
http://home.earthlink.net/~synthfred/h_toctop.htm (Fred's online edition)

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