The supply receives - 20 V from the rectifier/filter which is fed to the collector of the Darlington pnp pass transistor, a TIP105. The base drive to the TIP105 is supplied through penahan R5. The base of the TIP105 is driven from Vz terminal at pin 9, which is the anode of a 6.Dua-V zener diode that connects to the emitter of the uA723 hasil control transistor.
15-V 1-A Regulated Power Supply Circuit Diagram:
The method of providing the positive feedback required for foldback action is shown. This technique introduces positive feedback by increased current flow through resistors R1 and R2 under short-circuit conditions. This forward biases the base-emitter junction of the 2N2907 sensing transistor, which reduces base drive to the TIP105.
