Fluke 28IIEX Fluke 28IIEx User Manual - Page 36

Diode Tests, capacitors before you do a diode test.

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28 II Ex Users Manual Diode Tests WCaution To prevent damage to the Product or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before you do a diode test. Use the diode test to examine diodes, transistors, silicon controlled rectifiers (SCRs), and other semiconductor devices. This test sends current through a semiconductor junction, while it measures the junction's voltage drop. A good silicon junction drops between 0.5 V and 0.8 V. To do an out of circuit diode test, set up the Product as shown in Figure 7. For forward-bias measurements on a semiconductor component, put the red test lead on the component's positive terminal and put the black lead on the component's negative terminal. In a circuit, a good diode will cause a forward-bias measurement of 0.5 V to 0.8 V. A reverse-bias measurement can be different because of the resistance of other pathways between the probe tips. A short beep sounds if the diode is good (

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28 II Ex
Users Manual
26
Diode Tests
W
Caution
To prevent damage to the Product or to the
equipment under test, disconnect circuit
power and discharge all high-voltage
capacitors before you do a diode test.
Use the diode test to examine diodes, transistors, silicon
controlled rectifiers (SCRs), and other semiconductor
devices. This test sends current through a semiconductor
junction, while it measures the junction's voltage drop. A
good silicon junction drops between 0.5 V and 0.8 V.
To do an out of circuit diode test, set up the Product as
shown in Figure 7. For forward-bias measurements on a
semiconductor component, put the red test lead on the
component's positive terminal and put the black lead on
the component's negative terminal.
In a circuit, a good diode will cause a forward-bias
measurement of 0.5 V to 0.8 V. A reverse-bias
measurement can be different because of the resistance
of other pathways between the probe tips.
A short beep sounds if the diode is good (<0.85 V). A
continuous beep sounds if the measurement is
≤
0.100 V.
This measurement shows a short circuit. The display
shows “OL” if the diode is open.