TM 11-6625-539-15-2
The test set can be used to determine the type of
failure encountered, and some of the tests can be used
to verify the findings of other tests. The chart in para-
Test Set, Transistor TS-1836B/U is designed so that
graph 2-7 lists the types of failures that can be found
it is a safe instrument to use with semiconductor cir-
and the manner in which the test set can be used to
cuitry. The voltage and current levels that the instru-
determine the type of failure. An open and a shorted
ment can supply to the device are controlled so that
diode both give zero meter deflection on the in-circuit
diode measurement test. If the diode is shorted,
the accidental misplacing of leads will not damage
switching the meter to the C-E OHMS test will give
any semiconductor device; therefore, any device fail-
a 0-ohm reading. If the C-E ohms tests shows a resist-
ure would be caused by equipment operation and not
ance or an infinity reading on the meter, the diode
is open.
the manner which the test set is used.
a. Transistors.
Ohms (E-B, C-B, C-E)
Beta
Type of failure
Emitter-to-base
ohms
test.
Meter
indicates
infinity
or
Open emitter-to-base junction _ _ _ _
Beta reads infinity _ _ _
emitter-to-base
load.
Emitter-to-base
ohms
test.
Meter
indicates
0
ohm.
Shorted
emitter-to-base
junction
___
Test
set
cannot
be
set
for
BETA
CAL.
Test set cannot be set for BETA
Emitter-to-base
ohms
test.
Meter
indicates
low
re-
High leakage between the emitter-
sistance.
to-base
junction.
CAL.
Collector-to-base
ohms
test.
Meter
indicates
infinity
Open
collector-to-base
junction
____
Test
set
cannot
be
set
for
BETA
or collector-to-base load.
CAL.
Collector-to-base
ohms
test.
Meter
indicates
0
ohm.
Shorted collector-to-base junction ___ Test set cannot be set for BETA
CAL.
Collector-to-base
ohms
test.
Meter
indicates
low
re-
High
leakage
between
the
collector-
Test
set
cannot
be
set
for
BETA
sistance.
CAL.
to-base
junction.
Collector-to-emitter
ohms
test.
Meter
indicates
in-
Open collector-to-emitter _ _ _ _ _ _ _ _ _ Test set cannot be set for BETA
finity
or
the
collector-to-emitter
load.
CAL.
Collector-to-emitter
ohms
test.
Meter
indicates
0
ohm.
Shorted
collector-to-emitter________Test
set
cannot
be
set
for
BETA
CAL.
Test set gives reverse indication
Collector-to-emitter
ohms
test.
Meter
indicates
low
High
leakage
between
the
collector-
for
BETA
CAL.
to-emitter.
b. Diodes.
Meter indication
Ohm (C-E)
Type of failure
In-circuit diode measurement
Shorted diode_ _ _
0 meter deflection _ _ _ 0.
Open diode _ _ _ _
0 meter deflection _ _ _ Infinite or circuit
