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Author Topic: large value variable capacitor (sort of)  (Read 2690 times)

michael page

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large value variable capacitor (sort of)
« on: June 24, 2015, 06:36:23 PM »

Or it could be called 16 capacitor values from 4 capacitor.

Or supercap!

Im always just asking questions on here and not giving much back so I thought I'd post a useful discovery.

the positive leg of 4 capacitors in doubling values (or as close as possible to doubling values)  e.g.  22u 47u 100u 220u to tabs 1, 2, 3, 4 of a hexidecimal encoder thumbwheel switch. Link all 4 negative legs together and treat the 'common' of the switch as the positive of your super cap.  moving the thumb wheel through its 16 positions will give you 16 capacitors values from the lowest of the ones you have selected (22u) to the sum of the values selected (389u) in fairly even increments.

If necessary a further range of 16 smaller values can be achieved by putting a switch-in-able capacitor (in this example perhaps 22u) in series with the super cap.

Hope this is useful to someone, perhaps for tuning analogue drums or filters or something.   :)
« Last Edit: June 24, 2015, 06:38:56 PM by michael page »