Transformerless power supply field effect transistor

In Fig. 6.17 shows a diagram of a simple transformerless power supply the transistor BUZ41A.

Through connected in the circuit with a common drain transistor VT1 capacitor C3 is charged to a voltage of approximately 3 To less than the voltage at the Zener diode VD4.

AC voltage with a phase shift determined by the capacitance of the capacitor C1, opens the transistor VT2, which stops the charging of the capacitor C3 at the beginning of each the positive half-line voltage.

Author: A. P. Seman