MIL-PRF-1/ 37E
Table 1. Testing and Inspection -Continued.
Inspection
Method
Notes
Conditions
Symbol
Limits
Limits
Units
Min
Max
Conformance
5
inspection, part 3
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Group C;
-
---
Life test
power oscillation;
t = 500 hours
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Life-test end points:
a
---
12.0
is
-
1231
Peck emission
µA dc
-250
---
Isg1
-
1266
Primary grid emission
(control)
µA dc
-250
---
Isg2
-
1266
Primary grid
emission (screen)
NOTES:
1/
Adequate forced-air cooling must be provided to maintain base and anode seal temperatures below their
maximum rating. In all cases of operation, it is recommended that a heat-radiating connector, EIMAC HR-8,
or equivalent, be installed on the anode terminal, and that a socket and chimney be used which provide for cooling
of the seals. The following table applies to socket and chimney at sea level, and with air at 25°C, and should be
considered as minimum cooling requirements. The approximate pressure drop values given first are for the
socket as measured in the socket; those given next are for the socket as measured in the equivalent of a
pressurized chassis or plenum chamber. The data applies with maximum rated anode dissipation.
Socket and chimney
Socket and chimney
(pressure drop measured in socket)
(pressure drop measured in equivalent
pressurized chassis or plenum chamber)
Frequency
Airflow
Approximate pressure
Airflow
Approximate pressure
(cfm)
drop (In. H2O)
(cfm)
drop (In. H2O)
30 to 110 MHz
35
1.9
35
1.0
Below 30 MHz
20
0.6
20
0.42
Cooling air should be supplied before or simultaneously with the application of filament voltage,
and may be removed simultaneously with filament voltage. Operation at higher altitudes or higher ambient
temperatures will require an increase in cooling airflow.
2/
During all electrical tests involving application of filament power, forced-air cooling of the tube is
allowable and a heat-dissipating connector (EIMAC HR-8, or equivalent) may be used on the anode terminal.
3/
This test is to be the first test performed at the conclusion of the holding period.
4/
W hen type 8166 and type 8189 of MIL-PRF-1/1473 are physically identical, and have been made in the
same production run, differing only in high voltage processing and testing of type 8189, then one sample
may represent both types as the tests are identical.
5/
W hen type 8166 and type 8189 of MIL-PRF-1/1473 are physically identical and have been made in the same
production run, differing only in high voltage processing and testing of type 8189, then one life-test
sample may represent both types.
3