Hi What we are dealing with here is a transistor circuit that does indeed need the low value pot. It also needs to beL *very* stable. Lots of details on just how stable at:
HP5065A <http://phk.freebsd.dk/hacks/HP5065A/> Bob > On Dec 5, 2020, at 4:37 PM, ed breya <[email protected]> wrote: > > Paul, if the pot is 1 k, set up as a DC divider from a low-Z reference > voltage, and only lightly loaded by an amplifier circuit, you could try > upping it to a 2 k or 5 k, possibly 10 k, and get an immediate > resolution/set-ability boost, with little effect on the rest, and no other > part changes (except for whatever you need to get that nominal C-field > current in the right range - a separate issue). > > An easy way to assess the pot capability in-circuit, is to put a high > resolution (5 or 6 digits) DVM on the wiper or amplifier output, and just > pick some values of voltage, and see how closely you can tweak it to any > particular value. You can also observe the discreteness of the steps, the > lash, and maybe some interpolation ripple (non-monotonic behavior), by very > slowly rotating it while watching the DVM values. This will of course also > show if there are any bad spots on the pot, due to wear, corrosion, dirt, > deteriorated grease, etc. > > Ed > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
