INVERTER

PURPOSE:To prevent deflected excitation of an output transformer by controlling transistors by the width of the magnetic flux density of a transformer or the signal which detects the product of a voltage and time corresponding to said width. CONSTITUTION:The transistor Tr1 and Tr2 are driven by driving circuits DR 1 an DR2, and the an AC output is generated in a secondary winding n2 of the transformer T. The output voltage of the transformer T is detected by a voltage detection winding n3 and said detected voltage is applied to a linear inductance L via a rectifier REC in a magnetic flux density detecting circuit 7. The current flowing in the inductor L is converted to the magnetic flux detecting signal by a resistor R3, inputted to a comparator COP, and compared with a reference signal. A flip-flop circuit 3 is inverted by the output of the comparator COP, and the driving circuits DR1 and DR2 are controlled by the output of the circuit 3 and the output of a flip- flop 2.