Static inverter supplying small compressor from battery - has PTC resistor in series with resonant circuit tuning resistor

摘要

The static inverter has a PTC resistor (8) in series with the resistor (4) that determines the frequency of oscillation. Alternatively the resistor determining the frequency of oscillation may be shunted by a variable resistor in series with a PTC resistor. The two series resistors may be shunted by a triac switch that turns on and off as the voltage across the resonant circuit's coil rises and falls. The two series resistors are connected between a tapping on one primary winding of an output transformer and one pole of the battery. The ends of this primary are connected to the bases of the oscillating transistors. The inverter may be used for driving small compressors in coolers for caravans, etc.