[sdiy] Tempco question

Gene Stopp gene at ixiacom.com
Tue May 21 20:25:24 CEST 2002


Yeah sure - the v/oct trimmer should take up the slack, as long as the
tempco has the right "co".

Brings me to a related question - anybody got a handful of tempco's for
sale? I've seen the occasional email on the list, but I've never acted, and
now I forget who it could have been. Either that, or a pointer to a
distributor known to have them. Thanks all!

Best Regards,

- Gene


-----Original Message-----
From: Michael Schulze [mailto:michael.schulze at oberlin.edu]
Sent: Tuesday, May 21, 2002 10:47 AM
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Tempco question


Thanks to all who have been answering my questions!

I have found the tempco resistors I need, and I can get 5% ones for free.
These will be used to build a BERGFOTRON quad VCO board.  Will the 5%
tolerance be tight enough for the circuit?

The Bergfotron vco is a modification of the ASM1 VCO.  The tempco resistor
is the bottom resistor in a voltage divider between the output of the CV
summing amp and the input of the expo converter npn pair.  So we are talking
a +/- 50 ohm tolerance between a 56k and a 1k.   Geez, at 50/57000 I guess
that's 0.08% of the voltage divider.  Should be ok, no???



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