Downloaded from https://www.everyspec.com MIL-STD-1311D OSCILLATION TEST FOR CONVERTER TUBES 1. Purpose. To determine the capabilities of a converter tube to oscillate. 2. Oscillator grid current. Oscillator performance shall be measured according to the circuit shown on figure 1237-1. The specified voltages shall be applied to all elements through the specified circuit impedances. Oscillator performance shall be determined by the value of grid current for the specified resonant tuned impedance as obtained by the adjustment of R1. 2.1 The oscillator grid current test described herein and with the circuit components shown on figure 1237-1 is not usable with tuned impedances below 1,000 ohms.
The low impedances may result in oscillation under spurious conditions. Tube types with relatively high-transconductance levels which result in tuned impedance below 1,000 ohms should not be subjected to this test. Oscillator performance should be evaluated by another method. METHOD 1237A C1 - 100 pF R1 - 50,000 ohm L1 - 23.3 µ H C2 - 200 pF potentiometer Coil diameter - 1.25 inch C3 - 0.1 µ F R2 - 20,000 ohm ± 1 percent (wire Winding length - 0.992 inch C4 - 0.1 µ F R2 - 50,000 ohm ± 1 percent (wire Wire - No. 30 enamel copper C5 - 0.1 µ F M1 - Grid current meter Turns - 83 Tap - 33 turns from anode end FIGURE 1237-1. Converter tube test oscillator circuit.
METHOD 1237A 1237-1 7 January 1972