| 摘要 |
PURPOSE:To prevent the breakdown of a load, which is a material to be measured, due to an excessive reverse current and to make it possible to measure the reverse current with respect to the specified direction, by connecting the output stage of an output buffer circuit and the output of a voltage-error detecting circuit through a resistor. CONSTITUTION:For example, 5V is added to a voltage reference input, and 10V is added to a current reference input, an output terminal 11 tends to become +5V. As a result, the output of an operation amplifier 1 in an error detecting part (a) on the current side cannot pass through an output buffer (c). Only an operation amplifier 1 in the error detecting part on the voltage side effectively acts on the control of the output voltage. Even if a PNP transistor 5 is turned OFF, a current is made to flow through a bias resistor 6 bypassing the PNP transistor 5 from the operation amplifier 1 in the error detecting part on the voltage side. Therefore, even the reverse current with respect to the specified direction can be made to flow. Thus, even the current whose flowing direction is reverse to the specified direction can be measured.
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