[sdiy] Transistor Matching (was moog high pass flter)

[Tim Ressel]

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


__________________________________________________
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
http://mailplus.yahoo.com