15V variable power supply circuit
This 15v variable power supply electronic project is designed using 2N3055 transistors. Output voltage of this variable power supply can be adjusted in the range between 1.5 and 15 volts. This 2N3055 15v variable power supply can provide a maximum current of 500 mA. Stabilization is better than 2%, if the currents do not exceed 350 mA. Voltage is set using a potentiometer, and the presence of overload is announced by an audible indication of overload.
T4 transistor compare the voltage at the cursor P1 with the output. When this voltage is higher with 0.65 V than regulated voltage, T2 opens, leading to suppression of the current Darlington power stage, T3-T5. In this mode, the output voltage of the source is higher than 0.65 V reference voltage on the base of T4, which comes from a 15 V zener diode.