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.
The circuit shown serves as a direction indicator or arrow for bicycles, robots and other...
This circuit was found in an 1888 publication. However, since it uses common components, it can...
Featuring low output impedance and high input impedance, this configuration was found in a 1980s...