MIL-PRF-1/1426E
TABLE I. Testing and inspection - Continued.
1/ In pulsed operation, the peak inverse voltage exclusive of a spike of 0.05 s maximum duration, shall not exceed 5 kv during
the first 25 s following the anode pulse.
2/ The driver pulse, measured at the tube socket with the thyratron grid disconnected: tr = 0.35 s maximum; grid pulse duration
= 2 s minimum. The impedance of the drive circuit shall be 50 to 200 ohms.
3/ The anode circuit constants shall be chosen for a resonant charging condition of prr = 4,000 minimum. At epy = 24 kv and
ib = 580 a minimum, the rate of rise of the current pulse (dik/dt) shall be 5,000 a/s minimum. The pulse width (tp) shall be
2.4 s 10 percent. The grid pulse measurements at the tube socket with the thyratron grid disconnected shall be as follows:
tr = 0.35 s minimum, tp = 2.0 s maximum, Zg = 200 ohms minimum, Ecc = -70 V minimum.
4/ The anode temperature and grid seal temperature shall not exceed 350C at any time during this test.
5/ Anode voltage shall be applied as specified in 6/. Full anode voltage (epy = 24 kv) shall be reached within 5 seconds after
starting. The tube shall operate at the specified anode voltage for a total of 6 hours, which may include two interruptions during
the initial 30 minutes and one interruption during the last 5.5 hours.
6/ The tube shall operate satisfactorily on push button starting within two attempts when the anode voltage (epy) is applied to the
tube under test in such a manner as to rise from 0 to 18 kv minimum within 0.03 second. (The filter in the rectifier shall be
designed so that epy reaches at least 9 kv within 0.015 second). Any tube failing to start within three attempts will be
considered a failure.
7/ There shall be no artificial anode or envelope cooling directed onto the tube. Blowers or anode radiators shall not be used.
8/ The heat dissipater, Hughes Aircraft Co. Part No. 529033 (grid radiator), or equivalent shall be used during all tests of this
specification.
9/ This test shall be performed simultaneously with operation (1) test. Anode delay time measurement shall be made at the end
of 2, 4, and 30 minutes of the operation (1) tests. The anode delay time drift (tad) measurement is the numerical difference
between 2 minute and 4 minute, or 2 minute and 30 minute anode delay time readings, whichever is greater.
10/ Operation (2) shall be a continuation of operation (1) with the specified change in operating conditions made after 1 hour.
11/ This test shall be performed during the initial production and once each succeeding 12-calendar months in which there is
production. A regular double sampling plan shall be used, with the first sample of three tubes with an acceptance number of
zero, and a second sample of three tubes with a combined acceptance number of two. In the event of failure, the test will be
made as part of conformance inspection, part 2, code level D, with an acceptance level of 6.5. The regular "12-calendar
month" double sampling plan shall be reinstated after three consecutive samples have been accepted.
12/ The tube shall be tested by applying a peak forward anode voltage, as specified in the test conditions for the time jitter test
immediately after the tk. The tj shall be not greater than the amount specified after 120 seconds of operation.
13/ The tube shall operate at the specified anode voltage for a total of 6 hours which may include three interruptions during the
initial 30 minutes and three interruptions during the last 5.5 hours.
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