Constant frequency chopper for variable frequency AC generators - uses astable inverter multivibrator with npn transistor controlling output triac

摘要

The chopper circuit operates at a frequency largely independent of the voltage and frequency of an AC generator. The circuit is esp. applicable to trafficator lamps in vehicles having a magneto, such as mopeds. The source frequency may be between several Hertz and hundreds of kilo-Hertz and the voltage range between three and eighteen volts. The generator output is rectified in a full-wave bridge, the oscillator being an MOS inverter pair(1, 2) connected as an astable multivibrator working at about one Hertz. An NPN transistor(11) controls an output triac(X) in series with the trafficator flasher switch(Q).