N-channel JFET as Voltage controlled resistor gives unwanted Distorsion

Alec_t

Joined Sep 17, 2013
12,746
Do you want to introduce other methods to achieve a voltage controlled resistance, so that i can check them out?
PWM, by switching the ground end of a resistor at an ultrasonic frequency and low-pass filtering the result?
I haven't seen this method used in published circuits and I haven't tried this in the real world, but simulation looks promising -
PWM''dResistor.jpg

Edit:
The three waveforms are for respective different PWM pulse widths.
 

Attachments

Last edited:

Papabravo

Joined Feb 24, 2006
18,141
The traditional circuit for creating a DAC (Digital to Analog Converter) was to create an R-2R ladder of resitrors to convert a digital value into an analog value by means of controlling the total resistance of the ladder. I should point out this technique works best on a silicon die, and is less likely to be used with discrete parts. I is however possible to construct.

1637855590671.png
 
Top