Re: voltage to resistance convertor?


"Larry Brasfield" <donotspam_larry_brasfield@xxxxxxxxxxx> wrote in message
news:iRw7e.17$6A4.418@xxxxxxxxxxxxxxxxxx
> "Andrew Howard" <ask.me@xxxxxxxxxxxxx> wrote in message
> news:SLw7e.11499$5F3.11273@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> If I have a source of variable voltage ( a sweep generator for
>> example), is there any way to create a source of varying resistance in
>> proportion to the voltage?
>>
>> About the only way I can think of off the top of my head is a
>> light/LDR combination, but I doubt that would be very efficient or
>> accurate.
>>
>> Anyone have any better ideas? Preferably simpler ones, even if it is
>> slightly less accurate. Or maybe someone knows of a resistance sweep
>> generator...
>>
>> Thanks
>> Andrew Howard
>
>
> If your resistance range is not too large, and the
> signals you will impress across it is small enough,
> a quad MOSFET array can be made to perform
> that function with an op-amp controlling it.
>
> What input and output range to you need, over
> what frequency range, with what distortion?
>
> Another approach is to use a multiplier IC, hooked
> up as a divider, with voltage input and current fed
> back from the output to the input. But again, the
> required specs are necessary to proceed.
>
> --
> --Larry Brasfield
> email: donotspam_larry_brasfield@xxxxxxxxxxx
> Above views may belong only to me.


Thanks for the quick reply!

The resistance, I will need between 0 and 2k5.

Frequency, between about 0.2Hz and about 20Hz.

Distortion isn't really that important, I'll be using it to control
something that isn't all that precise anyway.

The input voltage can be between 0V and 9V. I can probably regulate it
to anything within that.

In case you are wondering, it is for a Guitar FX pedal I am semi-designing.

Thanks again,
Andrew Howard


.

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