How to Check and Replace Rectifier Diodes

How to Check and Replace Rectifier Diodes

Rectifier Diodes are very common in applications. If there are problems with rectifier diodes in the circuit, how should they be inspected and replaced?

Inspection method for rectifier diodes

First, remove all the Rectifier Diodes from the rectifier and use a multimeter of 100 × R or 1000 × Measure the two outgoing lines of the rectifier diode in the R ohm range (with the head and tail swapped once each). If the resistance values measured twice differ significantly, such as those with high resistance values ranging from several hundred K Ω to infinity, and those with low resistance values ranging from only a few hundred Ω or even less, it indicates that the diode is good (except for diodes with soft breakdown). If the resistance values measured twice are almost equal and the resistance values are very small, it indicates that the diode has been broken down and cannot be used. If the resistance values measured twice are both infinite, it indicates that the diode has been internally disconnected and cannot be used.

Rectifier diode replacement method

After the rectifier diode is damaged, it can be replaced with the same model of rectifier diode or other models with the same parameters.

Usually, Rectifier Diodes with high voltage withstand values (reverse voltage) can be replaced by rectifier diodes with low voltage withstand values, while rectifier diodes with low voltage withstand values cannot be replaced by Rectifier Diodes with high voltage withstand values. A diode with a high rectification current value can replace a diode with a low rectification current value, while a diode with a low rectification current value cannot replace a diode with a high rectification current value.