MIL-PRF-23648F
b. Mounting plates: Use Micarta, polytetrafluoroethylene, or equivalent, insulating material.
c. Temperature stabilization: Allow enough time for medium and thermistor to stabilize at required
temperatures.
d. Measurements: Measure zero power resistance at 25°C and 125°C. With the input voltage
disconnected, adjust the output indicator to the zero output position. Connect input voltage source
and measure zero power resistance. Disconnect the voltage source. If the output does not return
to its initial zero output position to within a tolerance equivalent to ±0.05 percent of the resistance
value, the thermistor shall be classified as defective.
4.8.3 Resistance ratio characteristic (see 3.5 and 6.8.4). Compute the resistance ratio using the zero
power resistance measurement at 25°C and 125°C (see 4.8.2).
MIL-STD-202. The following details shall apply. Two terminal leads of each thermistor shall be tested
(see tables III).
4.8.5 Short time overload (see 3.7).
4.8.5.1 Test procedures. The test procedure shall be as follows:
a. Obtain zero power resistance at 25°C.
b. Mounting: See 4.8.2.3a.
c. Provide a filtered regulated dc power supply or battery.
d. Ambient: Room temperature.
e. Using the value of dissipation constant and nominal resistance value specified (see 3.1), compute
the average value of Eth and Ith required to raise the thermistor to the maximum power rating.
Place the unit in a circuit accomplishing this.
f. Energize the circuit for 5 minutes.
g. De-energize the circuit for 10 minutes. Repeat this operation for ten complete cycles.
h. Examine thermistor for evidence of arcing, burning, or charring.
i. Sixty minutes removal from circuit, the zero power resistance shall again be measured as
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