Function of rectifier bridge stack:

The function of the rectifier bridge stack is to convert the alternating current with the level floating above and below the zero point into the unidirectional direct current through the unidirectional conduction characteristic of the diode.

To convert AC power into DC power, rectification is required. There are three forms of rectification: half wave, full wave and bridge. Half wave is the simplest, but because only half of the waveform of AC is used, the efficiency is low, and the impact on the power supply system is large. Full wave rectification requires a special transformer with a center tap, which is not suitable for rectifying the mains power. Therefore, bridge rectifier is the most suitable and bridge rectifier circuit is simply called rectifier bridge.

The rectified pulsating DC power becomes smooth DC power after capacitor filtering, and then is inverted into AC power with high frequency through oscillation circuit and switching circuit. Through voltage transformation and rectification, the stable voltages of + 12V, - 12V, + 5V and + 3.3V required by the computer are finally output.

Inspection of the whole rectifier bridge:

In normal operation, two AC input terminals of the full bridge The forward and reverse resistances are infinite;+;;-; The forward resistance value of the input terminal is infinite, and the reverse resistance value (the red pen is connected to the + ;, and the black pen is connected to the ; - ;) is about 20K. It is assumed that the digital universal meter (diode) is used for inspection, and the red pen is connected to - 39;, Black lead connected to+ 39; 0.8; Connect two ~; Both are about 0.4, and the red pen is connected with + 39;, The other three pins of the black pen must be infinite, otherwise it will be damaged rectification.

The rectifier full bridge is composed of four diodes and has four lead pins. The connection point of the negative electrodes of the two diodes is the "positive electrode" of the full bridge DC output end, and the connection point of the positive electrodes of the two diodes is the "negative electrode" of the full bridge DC output end.

The half bridge is composed of two diodes and three lead pins. The pins on both sides of the positive half bridge are the positive poles of the two diodes, i.e. the AC input end; The middle pin is the negative pole of the two diodes, i.e. "positive pole" of the DC output terminal.

The negative electrodes of the two diodes on the pins on both sides of the negative half bridge, i.e. the AC input terminal; The middle pin is the positive pole of the two diodes, i.e. "negative pole" of the DC output terminal. A positive half bridge and a negative half bridge can form a full bridge