Introduction to Bridge Rectifier
The bridge rectifier is made up of four silicon rectifier chips for bridge connection and externally packaged with insulating plastic. The high-power bridge rectifier is encapsulated with a zinc metal shell outside the insulating layer to enhance heat dissipation.
The role of bridge rectifier
The bridge rectifier is used in the AC generator power system. One of its functions is to convert the alternating current generated by the alternator into direct current, so as to supply power to the electrical equipment and charge the battery; the second is to limit the battery current to flow back to the generator to protect The generator is not burned out by reverse current. Silicon diodes have the characteristics of unidirectional conduction, that is, when a certain voltage is applied to both ends of the silicon diode (the anode of the power supply is connected to the anode of the diode, and the cathode of the power supply is connected to the cathode of the diode), the diode is turned on and current flows. Conduction, no current flows. In this way, current can only pass in one direction. People use this characteristic of diodes to make rectifiers. When an AC voltage is applied to the rectifier, only the positive half cycle of the alternating current is allowed to pass, and the negative half cycle does not pass, so the pulsating direct current is output at the negative end of the rectifier.
Bridge rectifier principle
There are many varieties of bridge rectifiers: flat, round, square, bench-shaped (in-line and patch), etc., and there are GPP and O/J structures. The maximum rectified current ranges from 0.5A to 100A, and the maximum reverse peak voltage ranges from 50V to 1600V.
The half bridge is to seal the half of the two diode bridge rectifiers together. Two half bridges can form a bridge rectifier circuit, and one half bridge can also form a full-wave rectifier circuit with a center tap of the transformer.
Choose the rectifier bridge to consider the rectifier circuit and working voltage.
rectifier bridge stack is generally used in full-wave rectifier circuits, and it is divided into full bridge and half bridge.
The full bridge is composed of 4 rectifier diodes connected in the form of a bridge full-wave rectifier circuit and packaged as a whole. The figure shows its appearance.
Bridge rectifier naming rules
There are 3 numbers in the name of general bridge rectifier (bridge rectifier), the first number represents the rated current, A; the last two numbers represent the rated voltage (number*100), V.
How to measure the quality of bridge rectifier
Use a digital multimeter to detect the quality of the bridge rectifier.
The rectifier bridge is to seal the rectifier tube in a shell. It is divided into full bridge and half bridge. The full bridge is to seal the four diodes of the connected bridge rectifier circuit together. The half bridge is to seal the halves of the two diode bridge rectifiers together. Two half bridges can form a bridge rectifier circuit, and a half bridge can also form a full-wave rectifier circuit with a center tap of the transformer. The rectifier bridge should be selected. Rectifier circuit and working voltage.
1. Half-bridge detection The half-bridge is composed of two rectifier diodes. By measuring whether the positive and negative resistance values of the two diodes inside the half-bridge are normal with a multimeter, it can be judged whether the half-bridge is normal.
2. Detection of the full bridge Most rectifier full bridges are marked with "+", "-", and "~" symbols (where "+" is the positive pole of the output voltage after rectification, and "-" is the negative pole of the output voltage , "~" is the AC voltage input terminal), it is easy to identify each electrode.
When detecting, you can measure the forward and reverse resistance values of each rectifier diode between the "+" pole and the two "~" poles, and between the "-" pole and the two "~" (the same as the measurement method of ordinary diodes) Whether it is normal, it can be judged whether the full bridge is damaged. If it is measured that the forward and reverse resistance values of the whip diode in the full bridge are 0 or both are infinite, it can be judged that the diode has been broken down or is open-circuit damaged.