UNI-T UT20B Operating Manual page 18

2. For forward voltage drop readings on any semiconductor component, place the
red test lead on the component's anode and place the black test lead on the
component's cathode.
The measured value shows on the display.
Note
l
In a circuit, a good diode should still produce a forward voltage drop reading
of 0.5V to 0.8V; however, the reverse voltage drop reading can vary depending
on the resistance of other pathways between the probe tips.
l
Connect the test leads to the proper terminals as said above to avoid error
display.
l
The LCD will display " " indicating open-circuit for wrong connection.
l
The unit of diode is Volt (V), displaying the positive-connection voltage-drop
value.
l
When diode testing has been completed, disconnect the connection between
the testing leads and the circuit under test.
Model UT20B: OPERATING MANUAL
Measurement Operation (8)
18