China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

A choke coil is a part used in electrical circuits to allow DC current to flow through while blocking AC current from passing. These coils are used in a number of electrical devices. When used as part of a radio’s circuitry, it falls into one of two frequency classes: audio or radio. Those used in circuits with higher frequencies use different core materials than those used in lower frequency circuits.

In electronics a choke is a version of a passive two-terminal electronic component called an inductor which is designed specifically for blocking higher-frequency alternating current (AC) in an electrical circuit, while allowing lower frequency or DC current to pass. Like other inductors, a choke usually consists of a choke coil of insulated wire often wound on a magnetic choke core

During the process of sending a signal through a circuit, the idea is to let the desired signal go through while filtering out other, unwanted signals. One type of unwanted signal is common-mode noise, which is filtered out by a common-mode choke coil. Power lines are an example of a source of common-mode noise. Without a coil, the power line would create a lot of electrical noise as it traveled to its destination, which would then be received on the other end and possibly cause interference with the signal.

Common-mode high pressure sodium ballast, where two coils are wound on a single core, are useful for prevention of electromagnetic interference (EMI) and radio frequency interference (RFI) from power supply lines and for prevention of malfunctioning of electronic equipment. They pass differential currents (equal but opposite), while blocking common-mode currents