Magnetic amplifier refers to which device?

• A. A saturable reactor type device that is used in a circuit to amplify or control.
• B. A device that measures magnetic flux
• C. A passive coil with no core
• D. A device that converts mechanical energy to electrical energy

Answer: (A)

Magnetic amplifier is a saturable reactor type device used to amplify or control a circuit. It works by using a ferromagnetic core with a main winding and a separate control winding. The control winding drives the core toward or away from saturation, which changes the core’s permeability and thus the inductance seen by the main winding. When the core is unsaturated, the main inductance is high and current is limited; when the core is driven into saturation, the inductance drops and more current can flow. A small control current can therefore modulate a much larger load current, providing amplification or regulation of the signal. This concept is different from devices that merely measure magnetic flux or from an air-core coil with no core, and certainly different from a machine that converts mechanical energy to electrical energy.