Question on transistor equivs

[Coyoteboy]

http://www.edn.com/contents/images/243221f1.pdf

I'm trying to create the above circuit but i cant get half of the
transistors the circuit uses. Can anyone tell from a glance whether
they likely to be specifics or will general purpose versions do the
same trick?

Any light shed would be a help in the dark

James

 

[loedown]

Analog circuitry is not really my forte, but Q2 would have to be what it is,
or very close, otherwise you will have to modify the circuitry heavily for
the calibrate / temp characteristics. It looks like some form of thermostat
control, or temperature differentiation circuit with feedback (oh no, the
end of my analog skills).

2N3906 are pretty garden variety

2N4401 are not very garden variety at all, and let me guess, these are the
ones you are having trouble obtaining?

Paul

 

[Rich Grise]

On Wed, 27 Apr 2005 05:52:42 -0700, Coyoteboy wrote:

http://www.edn.com/contents/images/243221f1.pdf

I'm trying to create the above circuit but i cant get half of the
transistors the circuit uses. Can anyone tell from a glance whether
they likely to be specifics or will general purpose versions do the
same trick?

Any light shed would be a help in the dark

Which transistors can't you get? In the US, they're all very common.

Digi-key, for example, has them all, and I'm sure other vendors have them
as well, although if you're on Mars or something, shipping might be a
little pricey. ;-P

Cheers!
Rich

 

[Coyoteboy]

The UK (next best thing to mars), hard to get most of them without
serious postage costs or minimum Ł20 orders. Makes small projects
unviable most of the time.