08:54
Faizan
Diodes allow electric current to flow in only one direction. Each diode has two leads--an anode and a cathode. Current may flow from the anode through the cathode, but not in the opposite direction. Certain types of diodes emit light as they conduct current while others allow only a maximum amount of voltage to pass through them. There are two ways to test diodes with a digital multimeter. One way uses the continuity function, the other uses a resistance measurement. Some multimeters have a diode test function.
Continuity Test
Set the multimeter to test for continuity. Plug the red test lead into the "+" (or ohms) connector jack, and the black lead into the common connector jack.
Touch the red test lead to the diode's anode lead. Touch the black lead to the diode's cathode lead. The multimeter should beep, indicating continuity is present. The cathode lead is often marked with either a contrasting band or a colored dot around the body of the component.
Touch the multimeter's black test lead to the anode and its red test lead to the cathode. The multimeter should not beep, indicating there is no continuity. The diode is working functionally if it passes both tests.
Resistance Test
Set up the multimeter to test for resistance and set the range for a low resistance--typically less than 1,000 ohms will work. Plug the red test lead into the "+" (ohms) connector jack and the black lead into the common connector jack.
Touch the red test lead to the diode anode and the black lead to the cathode. The multimeter should read close to 0 ohms for a functional reading.
Touch the black test lead to the diode anode and the red test lead to the cathode. The multimeter display should read infinite or nearly infinite for a functional reading.
Continuity Test
Set the multimeter to test for continuity. Plug the red test lead into the "+" (or ohms) connector jack, and the black lead into the common connector jack.
Touch the red test lead to the diode's anode lead. Touch the black lead to the diode's cathode lead. The multimeter should beep, indicating continuity is present. The cathode lead is often marked with either a contrasting band or a colored dot around the body of the component.
Touch the multimeter's black test lead to the anode and its red test lead to the cathode. The multimeter should not beep, indicating there is no continuity. The diode is working functionally if it passes both tests.
Resistance Test
Set up the multimeter to test for resistance and set the range for a low resistance--typically less than 1,000 ohms will work. Plug the red test lead into the "+" (ohms) connector jack and the black lead into the common connector jack.
Touch the red test lead to the diode anode and the black lead to the cathode. The multimeter should read close to 0 ohms for a functional reading.
Touch the black test lead to the diode anode and the red test lead to the cathode. The multimeter display should read infinite or nearly infinite for a functional reading.
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