- 1). Turn off the power to the device in situations where a diode is connected to the circuit. Locate the cathode and anode portion of the diode. A small colored strip on the component represents cathode side of the conductor, while the anode side conductor does not have a colored strip.
- 2). Turn on your multi-meter and set the device to read "Ohms". If your multi-meter features several different ohm range selections, choose the median range available on the device.
- 3). Connect the red (positive) multi-meter lead to the cathode side of the diode while connecting the negative lead of the multi-meter to the anode side. Note the reading and reverse the connections.
- 4). Check the reading again, with the connections reversed and note whether or not the reading increases significantly. If the reading does not increase when reversing the connections to the multi-meter, the diode may be faulty. The actual resistance readings are of no consequence; the amount of deflection seen in the reading will indicate proper diode functionality.
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