Downloaded from https://www.everyspec.com MIL-STD-1311D METHOD 1321 AC AMPLIFICATION The test shall be made with the specified input signal (Esig) at a frequency of 60 to 2,000 Hz. The signal shall be coupled to the grid of the tube with no bias supply, through a 0.1- µ F capacitor. A 10-Meg resistor shall be connected from the grid to ground. The internal impedance of the signal source shall not exceed 2,500 ohms. The resistance (Rp) in series with the anode shall be 0.5 Meg, unity power factor. The circuit capacitance (including the vacuum-tube voltmeter) shall have a reactance of not less than 5 Meg at the test frequency.
Qualification testing shall be made with Esig at a frequency of 400 Hz and with the output voltage measured by the Hewlett-Packard 400A vacuum-tube voltmeter, or equivalent. METHOD 1321 1321-1 19 April 1968