Specifications

17
E. Testing Diodes (See figure 7)
Warning
To avoid possible damage to the Meter and to the device under
test, disconnect circuit power and discharge all high-voltage
capacitors before testing diodes.
Use the diode test to check diodes, transistors, and other semiconductor
devices. The diode test sends a current through the semiconductor
junction, and then measures the voltage drop across the junction. A
good silicon junction drops between 0.5V and 0.8V.
To test a diode out of a circuit, connect the Meter as follows:
1. Insert the red test lead into the
HzΩ terminal and the black 
test lead into the COM terminal.
2. Model UT205: Set the rotary switch to
, diode measurement 
(
) is default or press BLUE button to select measurement 
mode.
Model UT206: Set the rotary switch to
Ω and press BLUE 
button to select
measurement mode.
3. 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
• 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.
• Connect the test leads to the proper terminals as said above to avoid 
error display. The LCD will display
indicating diode being 
tested is open or polarity is reversed. The unit of diode is Volt (V), 
displaying the forward voltage drop readings.
Measurement Operation (5)
red
black
Model UT205/UT206: OPERATING MANUAL