TRANSISTOR CHOPPER

PURPOSE:To eliminate the conversion of a magnet switch with a power source voltage by supplying the base current of a main transistor through a transistor which chops in a duty in response to a power source voltage and the exciting coil of a magnet switch. CONSTITUTION:A comparator 37 chops a transistor 11 in a duty in response to the power source voltage detected by an amplifier 38. Since transistors 12, 7 similarly operate, the constant current is supplied to the exciting coil 9 of a magnet switch 5 and the base of a main transistor 4. On the other hand, a comparator 36 chops a transistor 8 and hence the transistor 4 with the compared output of the triangular wave of the constant frequency outputted from an amplifier 39 with the output of an accelerator potentiometer 15.