TM 11-6625-539-14-4
7-20. Transconductance Test (FET Out-of-Cir-
N-channel and one P-channel. Coverage must in-
elude GM ranges of 0 to 250, 250 to 2500, and 2500
cuit
to 25,000.
a. Test Equipment and Materials. Three field
b. Test Connections and Conditions. As indi-
effect transistors whose transconductance values
cated below.
have been checked on a standard transistor tester
c. Procedure.
and whose values are known. At least one must be
Control settings
Step
Performance standard
Test procedures
Test
No.
Equipment
equipment
under test
1
N/A
Insert one field effect transistor
Indication on GM scale must in-
FUNCTION switch:
dicate transconductance of
FET.
into test jack on front panel.
device as determined by
R A N G E switch: to
standard test set within 5
setting appropri-
percent of full-scale range.
ate for device.
POLARITY switch:
NPN for N-chan-
nel FET's, PNP for
P-channel FET's.
2
N/A
Insert remaining two FET's
R A N G E switch: to
Indication on GM scale must in-
dicate transconductance of
into test jack on" front panel
settings appropri-
device as determined by
ate for second and
successively.
standard test set within 5
third FET succes-
percent of full-scale range.
sive] y.
POLARITY switch:
NPN for N-chan-
nel FET's, PNP for
P-channel FET's.
721. Transconductance Test (FET In-Circuit)
(2) One 100-ohm, 1-percent resistor.
( 3 ) One 4k-ohm, 1-percent resistor.
a. Test Equipment and Materials.
b. Test Connections and Conditions. As indi-
(1) Three field effect transistors-one N-chan-
cated below.
nel, one P-channel, covering GM range of 0 to 250,
250 to 2500, and 2500 to 25,000.
c. Procedure.
Contol settings
Step
Performance standard
Test procedures
No.
Equipment
Test
under test
equipment
Meter must indicate transcon-
Insert one field effect transistor
1
N/A
FUNCTION switch:
ductance for device under
FET.
into test jack on front panel.
test.
R A N G E switch: to
setting appropri-
ate for device.
POLARITY switch:
NPN for N-chan-
nel devices, PNP
for P-channel de-
vices.
Meter must indicate transcon-
resistor
100-ohm
Connect
2
N/A
Same.
d u c t a n c e . Value must be
across G-S terminals of tran-
within 10 percent of full-
sistor under test.
scale range of value indicated
in step 1.
7-13
