Abstract
The characteristics of a transistor inverter for a discharge lamp ballast are calculated. The inverter is composed of a power transistor, two inductors (L1, L2), three capacitors (C1, C2, C3) and a control circuit that drives the power transistor. Under appropriate values of L1, L2, C1, C2 and C3, the power transistor can be switched at zero voltage, which reduces the power dissipation in it. The inverter generates a high voltage ac output. At high resistance loads, the output voltage is several times the input voltage. At low resistance loads, the output currentis held constant. These features are suitable for a discharge lamp ballast. The dependence of the output voltage on trigger frequency and load resistance is calculated, and the design of the ballast is also described.
