electromagnetic interference. Filters furnished to the requirements of this specification contain shunting ceramic discoidal capacitors and series inductors \(FSC 5915\). Capacitors furnished to the requirements of this specification contain shunting ceramic discoidal capacitors \(FSC 5910\). For the purposes of this specification, feed-through capacitor types \(C circuit configuration\) are referred to herein as a filter. Passband power may be alternating current \(ac\) or direct current \(dc\) and the filters used primarily in the reduction of broadband radio frequency interference. This specification provides for two levels of product assurance requirements. Filters covered by this specification are capable of operation over the temperature range of -55 degrees C to +125 degrees C.

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MIL-PRF-28861D

4.6.5.1 Insertion loss (at temperature). This test may be conducted in conjunction with the capacitance

measurement (temperature and voltage) provided the insertion loss is read before the dc bias is applied at each

temperature. Filters shall be tested as follows:

a. The filters shall be located with an appropriate adaptor in a temperature chamber.

b. Load and no-load measurements shall be made at -55�C, +25�C, and +125�C. Measurements shall be

taken at a sufficient number of frequencies to plot a curve of insertion loss versus frequency over the

specified frequency range for each temperature. Alternatively, photographs of the display of a spectrum

analyzer or chart recordings may be used.

4.6.6 Voltage drop (see 3.11).

4.6.6.1 Voltage drop for ac filters. The voltage drop is the difference between the input voltage to the filter and the

output voltage of the filter when the filter is carrying rated current at rated voltage, with a resistive load at maximum

rated frequency (see 3.1). The method of voltage measurement is shown on figure 2. Measurements shall be made

by using equipment that will enable voltage differences of less than 0.1 volt to be read.

FIGURE 2. AC filters; measurement of voltage drop.

FIGURE 3. DC filters; measurement of series-element voltage drop at rated current.