Bridge rectifier circuit diagram and current reversal

Bridge rectifier circuit is the most commonly used rectifier circuit. This circuit, as long as two diode ports are added to form a "bridge" structure, will have the advantages of a full-wave rectifier circuit and at the same time overcome its shortcomings to a certain extent.

Figure (a) is a bridge rectifier circuit diagram, and (b) is a simplified drawing.

Current direction of bridge rectifier

In the positive half cycle of u2, D1 and D3 are turned on, and D2 and D4 are turned off. The current returns from the upper end of the TR secondary to the lower end of the TR secondary through D1 → RL → D3, and a half-wave rectified voltage is obtained on the load RL.

In the negative half cycle of u2, D1 and D3 are cut off, D2 and D4 are turned on, and the current returns from the lower end of the Tr secondary through D2 → RL → D4 to the upper end of the Tr secondary, and the other half-wave rectified voltage is obtained on the load RL.

In this way, a voltage waveform that is the same as that of full-wave rectification is obtained on the load RL, and the calculation of its current is the same as that of full-wave rectification, that is

UL = 0.9U2

IL = 0.9U2/RL

The average current flowing through each diode is

ID = IL/2 = 0.45 U2/RL

The maximum reverse voltage that each diode can withstand is

What is silicon bridge and what is bridge stack?

At present, the four rectifier diodes of a low-power bridge rectifier circuit are connected into a bridge and packaged into a rectifier device, called a "silicon bridge" or "bridge stack". It is easy to use, and the rectifier circuit is often simplified as shown in Figure Z Figure 1 (c) form.