Working principle and application of rectifier bridge

Rectification in rectifier bridge is a term. It works through the principle of unidirectional conduction of diodes. Simply put, diodes are unidirectional, with forward conduction and reverse cutoff. That is to say, a diode only allows its positive pole to receive positive electricity and its negative pole to receive negative electricity. A diode only allows current to flow in one direction, so when it is connected to an AC circuit, it can make the current in the circuit flow only in one direction, which is called "rectification". Among them, the one with two diodes is a half wave rectifier bridge, and the one with four diodes is a full wave rectifier bridge.

1. Rectification circuit: Utilizing a rectifier bridge with unidirectional conductivity, also known as a rectifier bridge stack. Convert 50Hz alternating current with varying direction and magnitude in the circuit into direct current with unchanged direction but still fluctuating magnitude.

2. Filtering circuit: By utilizing the property that the voltage across the capacitor C of the energy storage element cannot suddenly change, the capacitor C can be connected in parallel with the load RL of the rectifier circuit to filter out most of the AC components in the output of the rectifier circuit, thereby obtaining a relatively smooth DC current. In low-power rectifier circuits, capacitor filtering is often used.

3. Power Transformer: Convert the AC voltage of the power grid into the required AC voltage, which can be rectified to obtain the DC voltage required by electronic devices.

4. Voltage stabilization circuit: When the grid voltage or load current changes, the amplitude of the DC voltage output by the filtering circuit will also change accordingly. Therefore, the function of the voltage stabilization circuit is to stabilize the rectified and filtered DC voltage. In low-power DC power supplies, common types of rectifier bridge circuits include single-phase half wave, full wave, bridge, and triple equal, which have both AC and DC currents.

The working principle of a single-phase full wave bridge rectifier bridge circuit: Four diodes are used in the circuit, interconnected to form a bridge structure. By utilizing the current guiding effect of diodes, during the positive half cycle of the AC input voltage U2, the rectifier bridge diodes D1 and D3 conduct, while D2 and D4 turn off, resulting in an output voltage of positive upper and negative lower on the load RL; In the negative half cycle, exactly the opposite, D1 and D3 are turned off, D2 and D4 are turned on, and the direction of the current flowing through the load RL is consistent with the positive half cycle.

Therefore, by utilizing a secondary winding of a transformer and a rectifier bridge, it is possible to ensure that there is a constant direction of pulsating DC voltage and current on the load of the rectifier circuit during the positive and negative half cycles of the AC power supply.