[sdiy] Transistor Matching

[David Reichert]

While the topic is up, I would like to pose a beginner style question
which has most likely been brought up before, but I have yet to see it
myself.

Anyway, what exactly is involved in matching transistors? Which
parameters are matched and to what tolerance? How does one go about it?

If someone could answer this or point me to an appropriate source I
would much appreciate it.


> From: Tim Ressel <madhun2001 at yahoo.com>
> Date: Mon, 9 Dec 2002 17:02:54 -0800 (PST)
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Transistor Matching (was moog high pass flter)
> 
> Yo,
> 
> Question: How close does the trannies have to be
> matched for say a ladder filter? is 6mV close enough?
> 
> By the by, I breadboarded, for lack of a better name,
> a differential transistor matcher. I used a CA3096 to
> make both an NPN and PNP matcher. The idea is this:
> you can run two transistors at the same time, and tie
> them together to keep them at the same temperature.
> Also the voltmeter now reads the difference directly.
> Seems to work pretty well.
> 
> --tr
> 
> 
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