[sdiy] Bournes 300K pots...

Neil Johnson nej22 at hermes.cam.ac.uk
Thu Jun 6 19:52:48 CEST 2002


> > Ok, the only trouble I have here is that, to prevent loading the
> > potentiometer, the wiper load resistance needs to be at least 10 times the
> > track resistance.

> Yes, there is validity to your concern.  I am using the pots in a
> sequencer...so, no problem.  The input impeadence is in the 10's of
> megohms.

Yeah, that would be fine.  But that's a fairly high path impedance..what
about noise performance?  I guess being control voltages you can afford to
seriously filter them.

> For things like frequency controls on VCO's and the like...yeah, they
> are not really suitable.

True, even more so where AC signals are concerned....the thermal noise
alone would be huge!

> I will have to stick with the lower quality pots for now.

Keep yer eyes peeled!  Last year I found a place in the US that had trays
of 10k Bournes sealed pots, right-angled PCB mounting, with metal mounting
bushes (like on Tony Allgood's modules) that went for something like 30c a
piece...so I now have over 300 of them!!  Should keep me stocked for a
little while :-)

Neil

--
Neil Johnson :: Computer Laboratory :: University of Cambridge ::
http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
----  IEE Cambridge Branch: http://www.iee-cambridge.org.uk  ----




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