Loop resistance values by a muhifunctional tester may deviate from the real ones
when test an orbit attitude control engine in a complicated electromagnetic environment with
interferences．Such a test result is likely to complete distorte．The main reason is that there exists a
parasitical monofier circuit during the test．The paper puts forward a method of adding shock ob—
sorber capacitance in the test circuit．Test shows that this method can effectively overcome parasitical
monofier．