MIL-PRF-1/1325F
TABLE I. Testing and inspection - Continued.
Inspection
Method
Notes
Conditions
Acceptance
Symbol
Limits
Unit
MIL-STD-1311
Level
20/
Min
Max
Conformance inspection,
part 3 - Continued.
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Survival-rate life test
end points:
50
---
Ib
---
---
1256
Electrode current (2)
µA dc
(anode)
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9,000
Sm
---
---
1306
Transconductance
µmhos
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t
2,000
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cycles
10/ 14/
Group C;
Intermittent life
1501
Ef = 6.3 V;
Ebb = 250 V dc
Intermittent life-test
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end points:
W
---
0.90
Po
---
---
4250
Output power (1)
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Ic
-1.0
---
---
1266
Total grid current
µA dc
MegΩ
---
60
R
---
---
1211
Insulation of electrodes
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18/
Barometric pressure,
1002
Pressure = 8 ± 2
reduced
mmHg;
voltage = 300 V ac
1/
Test in capacitance jig RCA Capacity Adaptor Model H-1756E, or equivalent. A capacitance bridge operating frequency of 1.0 to
2.0 kHz may be used.
2/
The tube shall be vibrated perpendicular to the major tube axis through a frequency range from 5 to 500 Hz and back. From 5 to
50 Hz, the tube shall be vibrated at a constant displacement of .0400 ± .0025 inch (1.016 ± 0.064 mm). From 50 to 500 Hz, the
tube shall be vibrated at a constant acceleration of 10 ± 2 G. Total time to complete a sweep cycle shall be 10 ± 5 minutes.
a.
Each tube shall be vibrated for 60 seconds at the frequency which gives maximum vibrational output. If at the end of 60
seconds the vibrational output is still increasing, the vibration shall continue until there is no further increase.
b.
The tube shall be rejected for vibrational output voltage exceeding the limit specified herein or failure to pass the continuity
and shorts test. For sweep-frequency vibration record the Ep measured over the vibration-frequency range from 50 to 500 Hz
and for variable-frequency vibration record the Ep measured over the vibration-frequency range from 5 to 50 Hz.
3/
This test is to be the first test performed at the conclusion of the holding period.
4/
This test shall be performed in amplifier cavity Amerac Model No. 1244-1, or equivalent. Test frequency shall be 550 ±10 MHz.
Input = 0.2 W . W hen the amplifier has been tuned, adjust Ec for Ib = 20 mA dc.
5/
Transconductance (2) is the percent change in transconductance (1) of an individual tube resulting from a change in Ef.
6/
Tube supported at cathode and anode terminals with the grid disk centered. The supports shall be placed .938 ± .016 inch (23.83
± 0.41 mm) apart. Apply force to the grid disk without shock, perpendicular to the axis of the tube. Inspect for defects described in
MIL-PRF-1, appendix D, vacuum seal (metal-to-glass) defect classification.
7/
Electrical rejects may be used.
8/
W henever Ec is not specified on any test, the grid shall be grounded directly or through a grid resistor (if specified) except where
related MIL-STD-1311 test methods imply grid variance to accomplish the test.
4
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