17
Making Measurements
CHECKING DIODES
This procedure lets you check diodes,
transistors, and other semiconductors for
opens, shorts, and normal operation. It also
lets you determine the forward voltage and
polarity for diodes. (This is handy when you
need to match a diode).
1. Disconnect power from the circuit you
will test and discharge all capacitors.
2. Rotate the function dial to
¹
/§/Ω.
3. Repeatedly press
SELECT to select the
diode function.
§ appears on the right
side of the display.
4. Connect the black test lead to the
cathode or one pin of the component
you want to check.
5. Connect the red test lead to the anode
or the other pin of the component you
want to check, or remove one of the
leads of the component you want to
measure from its circuit and touch the
test leads across the component. Then
note the first reading.
6. Reverse the test leads and note the
second reading.
If one reading shows a value and the
other is overrange (
.OF appears) the
device is good. If
.OF appears during
both readings, the device is open. If
both values are very small or zero, the
device is shorted.
Ô
Checking Diode Polarity
Many diodes have a stripe or mark on one
side. The marked side of the diode indicates
CAUTION
Do not connect the test
leads to a source of
voltage with the functio
dial set to
¹
/§/Ω.Thi
could damage the mete
or the circuit being
connected.
Ô NOTE Ô
• When you test most
semiconductors, the
values might vary
depending on the
temperature.
• The values that
appear during a
diode check show
the actual forward
voltage (max. 1.2V).
If the voltage
exceeds 1.2V,
O.F
appears. This means
the diode check
cannot be made
using this meter.
To Next Page
Loading...
Need help?
General
