Voltage-controlled amplifier

A voltage-controlled amplifier is an electronic amplifier that varies its gain depending on a control voltage (often abbreviated CV).

They have many applications, including audio level compression, synthesizers, and amplitude modulation.

A crude example is a typical inverting op-amp configuration with a light-dependent resistor in the feedback loop. The gain of the amplifier then depends on the light hitting the resistor, which is provided by an optocoupled LED. The gain is then controllable by the constant current through the LED. This is the type of circuit used in "optical" audio compressors.

External links

• Examples of non-optical VCAs
• Has some schematics for VCAs
• Vacuum tube VCAs