DT830B Diode Test

The DT830B has the capability to measure a diode and find its forward voltage. On this particular meter, the voltage is in mV. This is very useful if for example you need to find the forward voltage of an LED to calculate the value of its series resistance.

Resolution and Accuracy

Measuring a Diode

To measure the forward voltage, set the range switch to the diode symbol position. The side where the band is drawn is the cathode, hence the other side is the anode. Connect the black lead to the side with the band (cathode), and the red lead to the other side. The meter should then display a number, and this is the forward voltage of the diode.

When the red lead connects to the cathode, and the black lead to the anode, the LCD should display "1", which means infinite resistance, or no conduction. When a diode conducts in one direction and provides its forward voltage value, but does not conduct in the opposite direction, then engineers normally say that it is a "good" diode.

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