Checking Diodes - Radio Shack 22-813 Owner's Manual

C D
HECKING IODES
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
3. Repeatedly press
SELECT
§
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
.OF
other is overrange (
.OF
device is good. If appears during
both readings, the device is open. If
both values are very small or zero, the
Ô
device is shorted.
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 function
dial set to
could damage the meter
or the circuit being
connected.
§
¹
/ / .
Ô
to select the
• 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,
appears. This means
the diode check
cannot be made
using this meter.
appears) the
§
¹
/ / . This
Ô
NOTE
O.F
17