Equus 3340 - Automotive DMM (10 MegOhm / UL) - Manual (Page 12)

1. Plug the RED test lead into the "
Ω Ω
" jack of the tester; plug
the BLACK test lead into the "COM" jack.
2. Set the tester’s Function/Range Selector Switch to the
position (see Controls and Indicators, Item 3).
3. Press the SEL button, as necessary, until the (AUTO) icon
is shown on the display.
NOTE: To obtain accurate readings, disconnect at least one
side of the item under test from the circuit or circuit board before
measuring resistance.
4. Place the RED test lead onto one side of the item being test-
ed and the BLACK test lead onto the other side of the item.
(Polarity does not matter when checking resistance).
5. Read the results on the display.
C. DIODE TEST
NOTE: A diode is a semiconductor device that lets current flow in
one direction only. If the diode to be tested is part of a circuit
(with other electronic components), you must isolate it from the
other components by disconnecting at least one side of it from
the circuit before testing. A good diode will show a low voltage
drop across its junction (0.5-0.8 volts for a silicon diode or about
0.3V for a germanium diode) when the leads are connected in
one polarity and a very high resistance (or open circuit) when
the leads are reversed (connected in the opposite polarity).
1. Plug the RED test lead into the jack of the tester; plug
the BLACK test lead into the "COM" jack.
2. Set the tester’s Function/Range Selector Switch to the
position (see Controls and Indicators, Item 3).
3. Press the SEL button, as necessary, until the icon is
shown on the display.
4. Place the RED test lead onto one side of the diode being
tested and the BLACK test lead onto the other side.
5. Read the results on the display.
6. Reverse the test leads and again read the results on the dis-
play. Compare the two readings. One reading should indi-
cate a voltage drop value; the other reading should indicate
an overrange (OL) condition.
See note above.
11
E
WARNING
To avoid electrical shock and/or damage to the multimeter,
ensure the power is removed from the circuit before any
DIODE testing procedure is conducted. Test diodes on de-
energized (dead) circuits only, never on live circuits.