| 摘要 |
PURPOSE:To prevent a voltage drop by a constant voltage circuit and to decrease a terminal voltage when a switch is turned on by connecting a constant voltage circuit in parallel with a detection circuit, connecting a switching circuit in series with a power supply and connecting a constant current circuit in parallel with the switching circuit. CONSTITUTION:The constant voltage circuit 2 is connected in parallel with the detection circuit 1 and an output of the circuit 1 turns on/off the switching circuit 3. Then, the current required for the detection circuit 1 with the switch turned off is supplied from the constant current circuit 6 connected in parallel with the switching circuit 3. A voltage VA between terminals (a), (b) is the sum of a voltage VR decided by the constant voltage circuit 2 and the voltage drop Vs of the switching circuit 3 and the voltage drop Vs is nearly 0.1V when the switch is turned on. Thus, the voltage drop VA between the terminals (a), (b) is nearly equal to the voltage VR across the circuit 1 and useless voltage drop with the switch turned on is prevented.
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