GB981066A - Improvements in and relating to electric inverter circuits - Google Patents

Abstract

981,066. Supply systems for discharge lamps. LICENTIA PATENT - VERWALTUNGS G.m.b.H. May 8, 1961, No. 16649/61. Heading H2H. [Also in Division H3] An inverter, more particularly for supplying discharge lamps, comprises two alternately conducting transistors connected in series with a series circuit tuned approximately to the inverter frequency, positive feedback being applied to the transistors in dependence upon the current in and the voltage across the load circuit. The inverter shown comprises two transistors connected in series across the supply and having a discharge lamp load L p connected in series with a choke L between the junction of the two transistors and the junction of two capacitors C1, C2 connected across the supply. Current and voltage feedback are transformers T1 and T2 cause the circuit to oscillate whereby the transistors conduct alternately. During each half cycle one of the capacitors 61, 62 is resonantly charged and the other is resonantly discharged through the load, the switch-over occurring when the transistor current is substantially zero, the resonant half-cycle being greater than the conducting period. Additional lamps may be switched into circuit in which case one of the capacitors C1, C2 may be omitted so that a single pole switch may be used (Fig. 3, not shown). When a different voltage is required for the lamp it may be fed through a transformer.