| 摘要 |
PURPOSE:To prevent poor inspection due to missetting while simplifying the circuit dispensing with a dedicated D/A converter by a method wherein after a constant current is applied to a load, the voltage given is compared with the prescribed value to determine the propriety thereof and the output voltage of a constant current circuit automatically clamped at the prescribed value. CONSTITUTION:In the embodiment, this is composed of a D/A converter 1 of the value of current applied, a D/A converter 2 for the prescribed value of a measuring voltage, an amplifier A1 for generating an applied current, a load 3 connected to a terminal T, a resistor R1 for detecting current flowing through the load 3, a differential amplifier A2 for detecting a voltage across the resistor R1, D1, D2, S1 and S2 for setting a clamping voltage, a comparator A3 and the like. With such an arrangement, the output of the comparator A3 is OFF, current flowing through the load 3 turns to a constant current according to the output voltage of the D/A converter 1 and when the load is abnormal, the voltage at the terminal T rises or falls. But it is checked by the output of the comparator A3 when exceeding the clamping voltage.
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