Making Measurements 2
U1253B User’s and Service Guide 47
Testin g Diodes
To test a diode, turn the power off to the circuit and remove
the diode from the circuit.
Set up the multimeter as shown in Figure 2- 12, then use the
red probe lead on the positive terminal (anode) and use the
black probe lead on the negative terminal (cathode) and
read the display.
Next, reverse the probes and measure the voltage across the
diode again (refer to Figure 2- 13 on page 49). The diode’s
test result is based on the following:
• A diode is considered good if the multimeter displays
“OL” in reverse bias mode.
• A diode is considered shorted if the multimeter
displays approximately 0 V in both forward and reverse
bias modes, and the multimeter beeps continuously.
• A diode is considered open if the multimeter displays
“OL” in both forward and reverse bias modes.
Disconnect circuit power and discharge all high-voltage capacitors
before testing diodes to avoid damaging the multimeter.
• The cathode of a diode is indicated with a band.
• This multimeter can display diode forward bias of up to approximately
3.1 V. The forward bias of a typical diode is within the range of 0.3 V to
0.8 V.
To Next Page
Loading...
