If the rectifier is found to be malfunctioning, it should be checked.
The main fault of the rectifier is the damage of the diode. When checking diodes, the following methods are commonly used.
1. Visual inspection method Use your eyes to directly observe whether the diode housing has burnt, cracks, etc. If the above phenomenon occurs, the diode is damaged.
2. The hand-touch inspection method touches the case of the suspicious diode with your fingers. If you feel that the temperature of the case is too high or even hot, it means that the diode has broken down or is seriously leaking.
3. Light test method
Use a battery as a power source, take an instrument bulb (the rated voltage of the bulb should be equal to the battery voltage), and check the unidirectional conductivity of the silicon diode. The method is shown in Figure 7: Connect a wire to each of the positive and negative electrodes of the battery and alternately connect them to the two electrodes of the silicon diode through the test lamp, and then test twice. If the test lamp is on once and then not, it means that the silicon diode is good; if it is on twice, it means that the silicon diode has been broken down and short-circuited and cannot be used; if the test lamp does not light up twice, it means that the silicon diode is internally open. damage.
4. Multimeter inspection method
Place the multimeter in the ohm block, measure the resistance of the silicon diode, and then reverse the positive and negative test leads to measure again. If the resistance measured twice is one large and one small, and the larger one tends to infinity, and the small one is almost close to zero, then this diode is good, as shown in Figure 8. You can also know the positive and negative ends of the diode while measuring. When the pointer indicates a small resistance value, the end of the negative test lead is the anode of the diode.
