Hi, all,
I'm doing a lab special for some folks in the physics department of the University of Oxford. It's an interesting wrinkle on the laser noise canceller, which is going to work with some HgCdTe photodiodes at 5 microns. (*)
These gizmos are probably significantly less linear than silicon diodes, so I'm giving them an offset current adjust pot so that they can tweak the cancellation point a little bit. Thus they're going to be adjusting that pot quite often.
Trouble is, all the trim pots I can find are ~200 cycles rated rotational life, or not rated at all.
Any fave longer-life trim pots?
Thanks
Phil Hobbs
(*) I'm getting a factor of nearly 10 improvement in cancellation bandwidth (in the spherical-cow SPICE universe) by putting a bandaid on the MAT14 supermatch quad NPN. It uses one SiGe:C NPN to make a Darlington, thereby returning nearly all the base current to the collector, and another one as a CE stage looking at the MAT14's base and driving the other SiGe's base to force the MAT14's base to stay still out to high frequency. I have to put in bias at the MAT14 base and take it out again from the collectors, but since I need an offset current pot anyway that's not much of a worry.