Single-phase bridge rectifier circuit

working principle:

(1) u2 positive half cycle

u2 instantaneous polarity a(+), b(-). Diodes VD1 and VD3 are forward-biased and turned on, while VD2 and VD4 are reverse-biased and turned off. The conductive circuit is a→VD1→RL→VD3→b, and the voltage polarity on the load is positive up and negative down.

(2)u2 negative half cycle

u2 instantaneous polarity a(-), b(+). Diodes VD1 and VD3 are reverse-biased and cut off, VD2 and VD4 are forward-biased and conductive. The conductive circuit is b→VD2→RL→VD4→a. The polarity of the voltage on the load is also positive up and negative down.