| 摘要 |
PURPOSE:To enable highly accurate diagnosis of a relay of a semiconductor test head with a relatively simple construction, by connecting two diodes in parallel between first and second relays in opposite polarity. CONSTITUTION:Diodes 13 and 14 are so set that a forward voltage drop is larger than that of a lead to an object to be measured. At the test of the relays, with the relays 2, 4 and 9 OFF, an output signal of a DC signal source is set at 20V and 1mA and a measured value of a current measuring module 1 is checked whether to be 1mA or not, whereby operating conditions of the relays 2 and 9 are diagnosed. Then, the relays 2 and 4 are turned ON while the relay 9 is turned OFF to diagnose operating conditions of the relay 9 from the measured value of the current measuring module 1. For the diagnosis of the relay 4, the output signal of the DC signal source is set 30V and 10muA to turn the relays 2 and 4 OFF, and a measured value of a voltage measuring module 11 is checked whether to be 30V or not, thereby diagnosing operating conditions of the relay 4.
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