AC choke is an inductor that restricts higher-frequency alternating currents(AC) while permits direct current (DC) and lower-frequencies alternating current (AC) to pass through its conductor in an electrical circuit.

AC choke usually consists of coils of insulated wire wound on a magnetic core that creates a magnetic field when current flows through it. The choke’s impedance increases with frequency. Its low electrical resistance passes both AC and DC with little power loss, but its reactance limits the amount of AC passed.

AC choke play an important role in an electrical power system. It absorbs power line disturbance and protects sensitive equipment. It provides reliable filtering solution to reduce harmonic currents, generated by inverters and drives in the power system as well as protecting variable speed drives and motors from voltage spikes and harmonics distortion.