MIL-PRF-1/1097J
NOTES:
This value is for operation under fixed-bias conditions. With cathode bias, Rg may be 0.5 MegΩ maximum.
1.
2.
Tie 1k to 2k; 1g to 2g; and 1a to 2a.
3.
This test shall be performed at the conclusion of the holding period.
4.
See "Reduced pressure (altitude) rating", and altitude, maximum peak voltage.
5.
Envelope temperature (TE) requirements, when measured in accordance with the temperature by conduction-band
measurement (method 1226), will be satisfied if a tube having bogey Ib (±5 percent) under normal test conditions, is
determined to operate at or above minimum specified temperature at any position in the life-test rack.
6.
This test shall be conducted on the initial lot and thereafter on a lot approximately every 12 months. When one lot has
passed, the 12-month rule shall apply. In the event of lot failure, the lot shall be rejected and the succeeding lots shall be
subjected to this test until a lot passes.
7.
Prior to this test, tubes shall be preheated a minimum of 5 minutes with all sections operating at the conditions specified
below. Test at specified conditions within 3 seconds after preheating. The 3-minute test shall not be permitted. Grid
emission shall be the last test performed on the sample selected for the grid-emission test.
Ef
Eb
Ec1
Rk/k
Rg/g
MegΩ
V
Vdc
Vdc
Ohms
15.0
250
0
200
0.5
8.
Test each unit separately.
A grid resistor of 0.1 MegΩ shall be added to each section.
9.
10.
The positive portion of the grid pulse shall be a rectangular wave meeting pulse shape requirement of method 1296. The
pulse shall be applied to the grid by means of a driving circuit which produces the specified peak pulse voltage directly at
the grid terminal with respect to the cathode. Grid resistance not exceeding 50 ohms may be inserted to prevent
oscillation, provided readjustment of grid drive is made to maintain the specified pulse amplitude directly at the grid
terminal. The pulse width, tp, shall be 10 ± 2 μs, and the duty factor, 0.9 percent to 1.1 percent. Self-excited life-test
circuitry is permissible provided any additional anode voltage drops during the time of the pulse are compensated for by
increasing Ebb. No fixed Ec1 need be applied under self-excited conditions.
11.
The grid pulse shall be a square wave meeting the pulse shape requirement of method 1296, and in addition the maximum
amplitude shall occur within the first 20 percent of tp, tp = 10 μs, and prr = 1,000 pps. The pulse shall be applied to the grid
by means of a driving circuit which produces the specified peak pulse voltage directly at the grid terminal with respect to the
positive end of the cathode resistor. Grid resistance, not exceeding 50 ohms, may be inserted to prevent oscillation
provided readjustment of grid drive is made to maintain the specified pulse amplitude directly at the grid terminal. Peak
currents shall be measured by means of a high impedance oscilloscope, or equivalent device, connected across a cathode
resistor of 1.0 ± 0.01 ohm. The specified limit refers to the maximum of the pulse amplitude. The variation of the output
pulse amplitude between 20 and 80 percent tp shall not exceed the specified limits for Ćik(tp).
12.
Acceptance sampling procedure shall be in accordance with "Base-strain test, miniature, sampling (method 1121), except
that data covered in "Acceptance and rejection criteria" shall be modified as follows:
a.
Accepted if no defectives for class "A", "B", or "C" defects, respectively (see method 112).
b.
Rejected if any defectives for "A", "B", or "C" defects, respectively.
5
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