| 摘要 |
PROBLEM TO BE SOLVED: To miniaturize a device and reduce the cost by specifying the voltage range of a current source which may be dropped by the operation of an active element when the output current of a prescribed current value is outputted from the current source within a reference voltage range, and inspecting the quality of the active element based on the output voltage. SOLUTION: An operator specifies an allowable range, e.g.±20%, for the voltage value of the output voltage V0 stored in a memory as a reference daum. A CPU calculates a reference voltage range and stores it in the memory. An output current of a prescribed current value is fed to the equivalent input circuit of an active element 23, e. g. a photodiode 24 and the equivalent output circuit, e.g. a photo-transistor 25, from a constant-current source 21, and the active element 23 is judged as satisfactory when the voltage value of the output voltage V0 of the constant-current source 21 measured by a voltage measuring circuit 22 is within the prescribed reference voltage range. This device can be miniaturized and the cost can be reduced without requiring a constant-voltage source, a resistor, and a relay.
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