18 October 2002
22 August 1997
PERFORMANCE SPECIFICATION SHEET
ELECTRON TUBE, NEGATIVE GRID (MICROW AVE)
TYPE 8964 1/
This specification is approved for use by all Depart-
ments and Agencies of the Department of Defense.
The requirements for acquiring the electron tube described herein
shall consist of this document and the latest issue of MIL-PRF-1.
Triode, planar, ceramic and metal.
See figure 1.
Mounting position: Any.
W eight: 2.5 ounces (71 grams) nominal.
6.0 ± 5%
T (Anode shank)
Replaces EIMAC type number Y-561.
The transit-time heating effect of the cathode may have to compensated for by a reduction in the heater voltage after dynamic
operation of the tube has started. This back heating is a function of frequency, grid current, grid bias, anode current, duty cycle,
and circuit design and adjustment. There is an optimum heater voltage which will maintain the cathode at the correct operating
temperature for any particular set of operating conditions. A maximum variation of ±5 percent from optimum is permitted. No
reduction in heater voltage is required to 500 MHz.
The maximum instantaneous peak grid voltage for pulse service shall be within the range of +250 to -750 volts.
Sufficient conduction, convection, or forced-air cooling shall be provided for the anode shank and all seals to limit the maximum
temperature to the specified value under all operating conditions. W here emphasis is placed on long and reliable life, lower
temperatures should be maintained.
W ith an anode dissipation of 100 watts and with an incoming air temperature of 25ºC maximum at seal level a minimum airflow of
12.5 cfm shall be directed across the anode cooler, using the cowl.
In all electrical tests involving application of heater voltage, conduction, convection, and/or forced-air cooling may be used to assure
operation within the maximum rated temperature limits.
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DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.
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