[sdiy] Bournes 300K pots...

Neil Johnson nej22 at hermes.cam.ac.uk
Thu Jun 6 17:07:40 CEST 2002


> about the "300K Bournes Pots" from electronic gold mine

The URL for the click-happy is:


$  1.00 for a pack of 2 (50.0c each)
$ 35.00 for 100         (35.0c each)
$299.00 for 1,000       (29.9c each)

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.  In this case, you're looking at a 3 Meg input (3M3
NPV), which means adding a buffer amp to each pot.  Yikes!  I certainly
wouldn't build a mixer with these pots.

Maybe for a sequencer this is fine -- I suspect that each pot wiper would
go to an analogue switch then to a high-Z buffer of some sort.

Is it just me, or is there some validity to my concern?  Generally, I work
with 100k input resistance, and 10k pots.


Neil Johnson :: Computer Laboratory :: University of Cambridge ::
http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
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