Omega HHM21 Manual page 11

Resistance and Continuity Measurements
1. Set the Function/Range switch to the resistance function.
2. Remove power from the equipment under test.
3. Connect the red test lead to the "VW " jack and the black test lead to the
"COM" jack.
4. Touch the probes to the test points. In ohms, the value indicated in the
display is the measured value of resistance.
5. The beeper sounds continuously, if the resistance is less than 50W ±30W .
WARNING
The accuracy of the functions might be slightly affected, when exposed to
a radiated electromagnetic field environment, eg, radio, telephone or
similar.
Diode Tests
1. Connect the red test lead to the "VW " jack and the black test lead to the
"COM" jack.
2. Set the Function/Range switch to the "
3. Turn off power to the circuit under test.
4. Touch probes to the diode. A forward-voltage drop is about 0.6V (typical for
a silicon diode).
5. Reverse probes. If the diode is good, 1 OL is displayed. If the diode is
shorted, ".000" or another number is displayed.
6. If the diode is open, 1 OL is displayed, in both directions.
7. If the junction is measured in a circuit and a low reading is obtained with both
lead connections, the junction may be shunted by a resistance of less than
1kW . In this case the diode must be disconnected from the circuit for
accurate testing.
" position.
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