Patent ID: 7015657

Claim:
A ballast for HID (High Intensity Discharging) lamp, said ballast comprising: a power unit for supplying DC (direct current); a converting unit having four switches and connected to said power unit for converting DC into AC (alternate current); a voltage-resistant electrocontrol switch connected to said converting unit and having at least one high-voltage diode and an electrocontrol switch, which are interconnected in parallel, said electrocontrol switch having a shell and high-voltage-resistant oil received in said shell, whereby said voltage-resistant electrocontrol switch is resistant to high voltage for AC passing therethrough; a high-voltage ignition unit connected to said voltage-resistant electrocontrol switch; a current sensor connected to said converting unit; and a control circuit connected to said converting unit, said power unit, said high-voltage ignition unit, and said voltage-resistant electrocontrol switch for controlling actions of the aforesaid elements of said ballast; wherein said current sensor is a resistor.