MIL-PRF-19E
c.
Test voltages for bridges: Measurements of resistance shall be made by using the test voltage specified in
table XIII. The test voltage chosen, whether it be the maximum or a lower voltage which would still provide
the sensitivity required, shall be applied across the terminals of the resistor. This same voltage shall be
used when ever a subsequent resistance measurement is made.
TABLE XIII. DC resistance values.
Total resistance
Maximum test
nominal (in ohms)
voltage
10 to
100 incl.
1.0
101 to 1,000 incl.
3.0
1,001 to 10,000 incl.
10.0
10,001 and above
30.0
4.7.3.1 Total resistance (see 3.8.1). The total resistance of resistors shall be measured between the terminals of
the resistance element with the contact arm against the low resistance end of the taper. The resistance value
obtained shall be compared with the specified nominal total resistance.
4.7.3.2 Resistance taper (see 3.8.2). Following the measurement of total resistance, a resistance measurement
shall be made at 30, 50, 70, and 100 percent of the electrical rotation. The percent of measured resistance verse
percent of electrical rotation shall be determined from values obtained as follows:
Taper A (linear)
(From 0 to 100 percent electrical rotation)
Resistance x 100
Percent measured
=
resistance
Total resistance measured
Tapers C and F (nonlinear)
(From 0 to 50 percent electrical rotation)
Resistance x 100
Percent measured
=
resistance
Measured resistance at 50 percent rotation x 10
(From 50 to 100 percent electrical rotation)
Resistance x 100
Percent measured
=
resistance
Total resistance measured
4.7.3.3 Minimum resistance (see 3.8.3). The contact arm shall be rotated to its extreme counterclockwise limit of
mechanical rotation. With the arm in this position, the resistance between the left terminal and the center contact
terminal shall be measured. The contact arm shall then be rotated to its extreme clockwise limit of mechanical
rotation. With the arm in this position, the resistance between the right terminal and center contact terminal shall be
measured. For resistors with actuated switches, the minimum resistance shall be measured with the switch on the
exact point where the shaft actuator makes mechanical contact with the switch actuator when moving so as to begin
to turn the switch off, Minimum resistance shall also be measured with the switch at the off position.
4.7.4 Torque (see 3.9)
4.7.4.1 Mounting. The resistors shall be mounted by their normal mounting means, and a maximum of 10 inch-
pound torque shall be used in tightening the mounting nut.
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