On 2010-01-27, Jim Wilkins wrote:
On Jan 27, 5:00*pm, "DoN. Nichols" wrote:
...I wonder whether using low TC mica capacitors
and hand-drawn resistors would produce something more stable. *...
* * * * * * * * DoN.

I was curious and checked the temperature change of several types of
caps with a Boonton meter. Baked-bean micas changed perhaps 5% from
ice water to a heat gun blast. Multilayer ceramics dropped about in
half when heated, tantalums much more. The 1% metal film resistors
that company used for everything didn't change much at all.

O.K. So the micas would probably have been an improvement. The
trimmer caps were ceramic ones in the low pF range. However, the
resistors which I had available were the old carbon composition
resistors (RC20GF???J IIRC). And I don't know how the CMOS thresholds
might have changed with temperature.

I *am* amazed that the multilayer ceramics had that much change.

Thanks,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---