How to measure the quality of rectifier diodes

If we find any problems with the rectifier diode, we can also measure it ourselves if we are not professional. Beginners can also use a multimeter. Before testing, first turn the multimeter's conversion switch to the RX1K position in the ohms range, and then short-circuit the red and black probes to zero the ohms.

Positive characteristic test. Connect the black probe (positive terminal inside the meter) of the multimeter to the positive terminal of the diode, and connect the red probe (negative terminal inside the meter) to the negative terminal of the diode. If the pointer does not swing to zero but stops in the middle of the dial, the resistance value at this point is the forward resistance of the diode, and generally the smaller the forward resistance, the better.

If the forward resistance is 0, it indicates that the die is short circuited and damaged. If the forward resistance is close to infinity, it indicates that the die is open circuited. Both short-circuit and open circuit pipes cannot be used.

Reverse characteristic testing. Touch the red probe of the multimeter to the positive terminal of the diode and the black probe to the negative terminal of the diode. If the pointer is at or near infinity, the diode is qualified.

Caution: Do not use RX1 gear to prevent excessive current from burning out the diode.