Testing Procedure For Diode - Komatsu PC130-7 Shop Manual

TESTING AND ADJUSTING
TESTING PROCEDURE FOR
DIODE
a Test an assembled-type diode (18-pin) or a diode
(2-pin) according to the following procedure.
a The conductive direction of an assembled-type
diode is shown in the following figure.
a The conductive direction of a diode is marked on
its surface.
1. When using a digital circuit tester
1) Set the circuit tester in the diode range and
check the indicated value.
a If an ordinary tester is used, the voltage
of the battery in itself is indicated.
2) Apply the red (+) test pin to the anode (P)
side of the diode and the black (-) test pin to
the cathode (N) side and read the indicated
value.
3) Judge the condition of the diode from the
indicated value.
• The indicated value does not change:
There is not continuity (Defective).
• The indicated value changes: There is
continuity (Normal) (Note).
Note) In the case of a silicon diode, the cir-
cuit tester indicates a value of 460 –
600.
20-146
(1)

TESTING PROCEDURE FOR DIODE

2. When using an analog circuit tester
1) Set the circuit tester in the resistance range.
2) Apply the test pins as shown below and
check movement of the pointer.
i) Apply the red (+) test pin to the anode (P)
side of the diode and the black (-) test pin
to the cathode (N) side.
ii) Apply the red (+) test pin to the cathode
(N) side of the diode and the black (-) test
pin to the anode (P) side.
3) Judge the condition of the diode from move-
ment of the pointer.
• The pointer does not move in i) above
but moves in ii): Normal (Moving angle
(Resistance) depends on the type and
measurement range of the circuit tester,
however)
• The pointer moves in both i) and ii):
Defective (Internal short circuit)
• The pointer does not move in either of i)
and ii): Defective (Internal disconnection)
PC130-7