djm@nmtvax.UUCP (12/19/85)
[Let my lines go, oh Eater of Lines! No, I don't believe in it, but....]
I have a somewhat (hopefully) simplistic question:
Is it possible to use a FET as a solid-state potentiometer, and if
so, what sort of driver do you need for it (AC, DC offset from ground, ...)?
The application is digitally controlled volume, resonance of filters, etc.
If I can use D/A converters driving some simple pot-equivalents, it would
make life fairly easy, but I'm not familiar enough w/ analog type stuff
to know if it'll work. Comments?
Dieter Muller
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Choose a disclaimer, any disclaimer. Now hold it so I can't see it....larry@kitty.UUCP (Larry Lippman) (12/22/85)
> Is it possible to use a FET as a solid-state potentiometer, and if > so, what sort of driver do you need for it (AC, DC offset from ground, ...)? > The application is digitally controlled volume, resonance of filters, etc. > If I can use D/A converters driving some simple pot-equivalents, it would > make life fairly easy, but I'm not familiar enough w/ analog type stuff > to know if it'll work. Comments? Your desire has been made easier to fulfill by a number of IC products on the market. Try an Intersil P/N VCR2N, VCR4N, VCR3P or VCR7N. These are JFET integrated circuits billed as "Voltaged Controlled Resistors". A simple DC voltage is used to control the JFET gate and hence the effective resistance. You may also wish to look at: (1) the National Semiconductor P/N LM1035 Dual DC Operated Tone/Volume/Balance Circuit which is an IC providing DC control of the above named functions; (2) Motorola P/N MC3440P Electronic Attenuator IC. === Larry Lippman @ Recognition Research Corp., Clarence, New York === === UUCP {decvax,dual,rocksanne,rocksvax,watmath}!sunybcs!kitty!larry === === VOICE 716/741-9185 {rice,shell}!baylor!/ === === FAX 716/741-9635 {G1, G2, G3} ihnp4!/ === === === === "Have you hugged your cat today?" ===