Single ended converter responding to less than one volt - has simple transformer with only two windings, one in collector circuit and other in base circuit with variable resistor

摘要

The converter, for producing a DC output voltage, responds to an input voltage of only 0.9 volts whilst using a simple transformer with only two windings. The switching transistor is connected in series with one of the windings and receives the input voltage. The first winding (11) is in series with the transistor's collector and the second winding (14) is in series with a resistor (17) between the transistor's base and one supply pole. This fixed resistor is shunted by a variable resistor comprising a second transistor (16). The output (20) is taken from the switching transistor's collector.