Pointer multimeter to measure the rectifier diode good or bad method
Rectifier diodes are mainly used in rectifier circuits, using the unidirectionality of the diode to turn alternating current into direct current. Its rectification form has half-wave rectification and full-wave rectification.
Rectifier diodes can also fail, the fault manifested in the diode short-circuit, disconnection and so on.
Detect the diode good or bad available pointer multimeter, can also be used to detect the digital multimeter. The following electrician home to talk about the pointer meter test to determine the good and bad rectifier diode.
Pointer multimeter test rectifier diode good or bad
Diodes have unidirectional conductivity. That is, plus forward voltage conduction, plus reverse voltage cutoff. Its forward resistance is small, reverse resistance is large, which is the basis for detection.
First, usually, for a single rectifier diode, the test will first be placed in the multimeter ohm file Rx100 or Rx1K file. The two pens are connected to the two leads of the diode, measured resistance. Then the two pens will be switched to measure the resistance value again. Finally, the results of the two measurements for comparison.
If a large resistance value, a small resistance value, indicating that the rectifier diode is normal. When the resistance is small, the black pen is connected to the diode's positive pole, the red pen is connected to the diode's negative pole.
If the two resistance values are very large, it means that the diode is disconnected.
If the two resistance values are very small, the diode short circuit.
It should be noted that the choice of different gears, the measured resistance value will be different.
Second, the actual maintenance, often to weld the diode from the circuit, which is more trouble. In fact, the rectifier diode will not be welded down, direct online testing can also be a simple method, the effect is good, and now share it for reference use.
The power equipment will be normal power (alternating current), the multimeter to AC voltage gear, according to the rectifier voltage range to choose a specific gear, the red pen connected to the rectifier diode positive, black pen connected to the negative, measured by an AC voltage value. And then the pen to the right, and measured a voltage value. In the same way, the multimeter range dial to DC voltage, measured a DC voltage value. Then compare the results.
If the first measured AC voltage value is about twice the DC voltage value, and the second measured AC voltage is zero, indicating that the rectifier diode is normal.
If the difference between the two measured AC voltage values is not large, the diode has broken down.
If the two measured voltage values are zero, the diode has been short-circuited.
If the second measured value is neither zero nor equal to the first value of the diode performance deterioration.
