Steps to check a diode with a multimeter, follow these steps:
- Set the multimeter to diode test mode, represented by a diode symbol or the letters “diode” on the display.
- Connect the multimeter’s positive lead (usually the red one) to the anode of the diode and the negative lead (usually the black one) to the cathode of the diode.
- Note the reading on the multimeter display. In a functioning diode, the reading should be low resistance in one direction and high resistance in the opposite direction.
- Reverse the leads and take another reading. If the diode is functioning properly, the reading should be high resistance in this direction.
- Compare the readings to the manufacturer’s specifications for the diode in question to determine if it is functioning correctly.
If you do not have a multimeter with a diode testing mode, you can perform a simple resistance test to check the diode. Here are the steps:
- Set the multimeter to the resistance (Ω) measurement mode.
- Connect the positive lead of the multimeter to the anode of the diode and the negative lead to the cathode.
- Observe the reading on the multimeter display. If the diode is functioning properly, you should see a low resistance value (typically a few ohms) in one direction and high resistance (typically several megaohms) in the opposite direction.
- Reverse the leads and repeat the test. The multimeter should show high resistance in this direction.
- Compare the results to the specifications for the specific diode you are testing to determine if it is functioning correctly.
Note: This resistance test will not give you the voltage drop across the diode, but it can give you an idea of whether the diode is conducting or not.