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

Metal halide (MH) lamps consist of an arc tube (also called a discharge tube or "burner") within an outer envelope, or bulb. The arc tube may be made of either quartz or ceramic and contains a starting gas (usually argon), mercury, and MH salts. Traditional quartz MH arc tubes are similar in shape to mercury vapor (MV) arc tubes, but they operate at higher temperatures and pressures.

MH lamps start when metal halide ballast supplies a high starting voltage higher than those normally supplied to the lamp electrodes through a gas mixture in the arc tube. The gas in the MH arc tube must be ionized before current can flow and start the lamp. In addition to supplying the correct starting voltage, the ballast also regulates the lamp starting current and lamp operating current.

Capacitors in metal halide lamps are known as electrical ballasts. They sit between the lamp's electrical input and each of the lamp's arc tubes. Current passes in through the first of the capacitor's conductors. It physically cannot pass through the dialectric barring it from the conductor connecting to the arc tube. This generates a difference in electrical potential between the two conductors, and as the difference grows, it creates an electrical field within the dialectric. As the field remains constant, current passes into the arc tubes. Electrical current with the gas in the arc tubes causes the tubes to glow. The level of brightness stays constant only because the field generated by the dialectric produces a steady current that would not be present if the arc tube were connected directly to the electrical input.