TM 11-6625-539-14-4
meter indication by the setting of the RANGE
switch.
(7) Check to see that the beta reading is
greater than the minimum allowable value listed
in section II of appendix D for the device under
test. Reject the transistor if beta is less than listed
value.
(8) Remove the device from the transistor
socket.
b. Leakage Test. Make the out-of-circuit leakage
test (Ico) as follows:
(1) Position the POLARITY switch to PNP or
NPN, whichever is applicable.
(2) Operate the FUNCTION switch to ICO, IR.
(3) Operate the RANGE switch to X 10. Check
for meter zero. If necessary, zero the meter using
the METER ZERO control.
(4) Check the allowable leakage value for the
device as indicated in section II of appendix D.
Operate the RANGE switch to X 0.1, X 1.0, or X 10
as required.
(5) Install the transistor in the transistor
EL6625-539-14-4-TM-3
socket on the front panel. Be sure that you insert
the base, collector, and emitter leads respectively
1. Captive screw
2. Battery
into the B, C, and E socket contacts. If necessary
3. Battery compartment cover
for lead identification, refer to transistor base
data in section V of appendix D.
(6) Read leakage on the ICES, IC O, IR scale of
the meter. Multiply the reading by the setting of
that none of the cells is defective or connected in
the RANGE switch.
reverse.
(7) Check to see that the leakage reading is
less than the maximum allowable value listed in
2-9. Out-of-Circuit Testing of Bi-Polar Tran-
section II of appendix D for the device. Reject the
sistors
transistor if leakage is greater than that listed,
(8) Remove the device from the transistor
a. Beta Test. The beta test is the most signifi-
socket. Turn the POLARITY switch to OFF.
cant hi-polar transistor test. Proceed as follows to
make the beta test out of circuit:
(1) Operate the POLARITY switch to PNP or
2-10. In-Circuit Testing of Bi-Polar Transistors
NPN, whichever is applicable.
(2) Operate the FUNCTION switch to BETA.
Two in-circuit tests are normally made for hi-polar
Operate the RANGE switch to X10.
transistors. These include beta and leakage tests
(3) Check to see that the meter pointer is
similar to those used for out-of-circuit testing.
exactly zeroed. If it is not, adjust the METER
a. Beta Test.
ZERO control to provide an exact zero indication.
(1) Operate the POLARITY switch to PNP or
(4) Operate the RANGE switch to X 0.1.
NPN, whichever is applicable.
(5) Install the transistor into the transistor
(2) Operate the FUNCTION switch to BETA.
socket mounted on the front panel. Be sure to in-
(3) Operate the RANGE switch to X 10. Check
sert the base, collector, and emitter leads respec-
to see that the meter pointer is exactly zeroed. If
tively into the B, C, and E socket contacts. If
it is not, adjust the METER ZERO control to
necessary for lead identification, refer to transis-
provide an exact zero indication.
tor basing data in section V of appendix D.
(4) Operate the FUNCTION switch to OHMS.
(6) Read the value on the BETA scale. Oper-
(5) Operate the RANGE switch to X 1.0.
ate the RANGE switch as necessary. Multiply the
