Downloaded from https://www.everyspec.com MIL-STD-1311D METHOD 1256 ELECTRODE CURRENT 1. Purpose. To measure the particular electrode current at the point in the circuit and in the manner specified. 2. Equipment. Suitable instruments as required for the measurement with precautions being observed to eliminate any pulse or rf current not intended to be included in the measurement. 3. Procedure. a. Electrode current. With the specified voltages and currents applied, the current flowing to the electrode concerned shall be within the specified limit(s). b. Tube operation time.
Tube operation time is the time (t1) required for the anode current to reach a specified percentage of the anode current measured at the conclusion of a specified period of time (t2). The tube filament shall be energized instantaneously from a substantially zero impedance source. The tube shall have had no potentials applied for a period of at least 1 hour prior to the performance of this test. Tubes intended principally for use with zero bias or fixed bias shall be tested under anode current test conditions with zero or fixed bias.
Tubes intended for use with self bias or those intended for use with self bias or those intended for use with either self bias or fixed bias shall be tested under self bias anode current conditions. The time (t1) for the anode current to reach the specified percentage of the anode current measured at the conclusion of the time (t2) specified shall not exceed the maximum specified for the individual tube type. NOTE: When electrode-current tests are made on converter-type receiving tubes, no signal shall be applied to the signal gird. METHOD 1256 1256-1 19 April 1968