This VCA was found in the July 1988 issue of Radio Electronics magazine. It uses an OTA op amp and has its gain adjusted by the voltage at the gain input.
This circuit is from a Popular Electronics from the 90s. Its gain is 22 dB and can be used as a...
This circuit was found in an article in Radio Electronics magazine from October 1962. At that...
This circuit can be implemented with other operational amplifiers. The formulas for calculating the...