| 摘要 |
PURPOSE:To measure the change of constants of constituting parts of an electric apparatus having a large variance of the power source voltage such as an electric apparatus mounted on a car with a high precision and make the test equipment small-sized and light-weight, by using the power source in an object to be tested to perform the test. CONSTITUTION:A voltage E0 of an object to be tested is inputted to an operation controlling part 2 through an A/D converter 17 and an interface circuit 18 to calculate a voltage E=0.63E0 corresponding to a time constant value, and this voltage E is used as the set value of a comparator 6 through a D/A converter 5. A time constant command is outputted from the operation controlling part 2 to excite a relay coil 15 of an object 10 to be tested through an interface circuit 4 and an output line 16, and a relay contact 14 is made to apply a voltage to the series circuit of a resistance 12 and a capacitor 11, and the comparator 6 is turned on. The comparator 6 monitors a terminal voltage E1 of the capacitor 11; and this voltage reaches the set value, the level is changed to turn-off. The time when the comparator 6 is turned on is counted by a counter circuit 8, and the time constant is measured by the operation controlling part 2. |
