| 摘要 |
<p>PURPOSE: To minimize the error and loss in detection by extending the detection range of current so that independent detections can be performed. CONSTITUTION: A rectified voltage current is supplied from an input terminal Ti. Resistors 1 and 2 are serially connected between the input terminal Ti and an output terminal To. A load is connected to the output terminal To. The resistor 1 is provided between the emitter collectors of a transistor 3, and a constant current detecting circuit 5 is also provided between them. The base of the transistor 3 is connected to a control circuit 4, and controlled by the control circuit 4. The constant current detecting circuit 5 detects the current from the voltage between both ends of the resistor 1. A current detecting circuit 6 is connected to both ends of the resistor 2 to detect the current from the voltage between both ends of the resistor 2. A small current is detected in the constant current detecting circuit 5, and a heavy current is detected in the current detecting circuit 6. When the small current is detected in the constant current detecting circuit 5, a signal is supplied to the control circuit 4, and the control circuit 4 supplies a signal for increasing the impedance of the transistor 3 to the base of the transistor 3.</p> |
