[sdiy] OTA as Voltage Controlled Resistor

[Justin Owen]

-----Original Message-----
From: Lanterman, Aaron [lanterma at ece.gatech.edu]

>> The LM13700 data sheet shows a schem (Fig. 10) for a 'Floating Voltage Controlled Resistor' - this seems to be a double-ended circuit as opposed to the FET-based circuits (and the the LM13700 circuit in Fig. 9) which (from memory) are single-ended.
>> 
>> My questions...
>> 
>> 1) Can the double-ended circuit be used to replace a standard discrete resistor - i.e. is either 'end' replacing a leg/pin of a resistor?


> I've had students off-and-on over the years experiment with the double-ended version. It never worked out quite the way they hoped.


Hi Aaron,

Any idea why this was?

Thanks