tempcos

[List, Christopher]

You are correct Tom. I discovered that with one batch of tempcos I got from
KRL/Bantry Components (of Manchester, NH, USA). They were special 1/2%
tolerance models, however. When I got their 1% models, the y worked great.
They made differently, and they didn't exhibit the inductance effects.

Note that the inductance is not a real problem, provided you are a little
enterprising. Most schems show the tempco in the feedback loop of the
summing op-amp for the v/oct inputs. Inductance here will cause a problem.
If you move them tempco to the voltage divider between the summing op-amp
and the matched transistors, the inductance is _never_ an issue.

I wouldn't consider any sort of temp-comp scheme other than tempco
resistors, and would like to see more people get and sell stock (as I did
for this list a couple of years ago). The reduction in parts count, power
consumption, and complexity make them the only real choice (ahem, IMHO that
is)...

Isn't Paul still selling them?

- CList

> -----Original Message-----
> From:	Tom May [SMTP:tom at go2net.com]
> Sent:	Monday, September 13, 1999 8:35 PM
> To:	DIY
> Subject:	Re: tempcos
> 
> "tomg" <vco at mindspring.com> writes:
> 
> > I talked to a few people today. The best deal I have so far is to have
> them
> > 
> > made especially for us. I need 10 people to take 10 psc.
> > 
> > Here's the deal. 1K 3300ppm 1/4w 1%, 10  for $22.00 includes s&h.
> 
> Wasn't there some discussion here a few years back about whether some
> of the tempco resistors were somewhat inductive, which caused some
> kind of badness?  I wonder how these ones would rate.
> 
> fTom.