Diode Tests - Fluke 233 User Manual

Diode Tests

WCaution
To prevent possible damage to the Meter or
to the equipment under test, disconnect
power and discharge all high-voltage
capacitors before a diode test.
Do a diode test on diodes, transistors, silicon controlled
rectifiers (SCRs), and other semiconductor devices. This
function sends a current through the semiconductor
junction and then measures the voltage drop across the
junction. A good silicon junction drops between 0.5 V and
0.8 V.
To do a diode test on a diode out of a circuit, set up the
Meter as shown in Figure 4. For forward-bias
measurements on a semiconductor component, put the
red test lead on the positive terminal of the component
and put the black test lead on the negative terminal of the
component.
In a circuit, a good diode has a forward-bias
measurement of 0.5 V to 0.8 V. A reverse-bias
measurement includes the resistance of other pathways
between the probes.
A short beep sounds if the diode is good (<0.85 V). A
continuous beep sounds if the measurement is 0.100 V
or short circuit. The display shows "" if the diode is
open.
True-rms Remote Display Digital Multimeter
How to Make Measurements
21