| 摘要 |
PURPOSE:To simplify a circuit while certainly performing operation, by applying constant voltage to both terminals of a temp. sensitive part having a thermistor and a resistor connected thereto in series to flow a specific current to the thermistor and generating a temp. abnormality alarm signal on the basis of the output of the amplifier connected to both terminals of the resistor. CONSTITUTION:The temp. of the circuit part 2 received in a thermostatic tank 1 of which the temp. was controlled by a control circuit 3 is held in a predetermined range and constant voltage is applied to a temp. sensitive part having a thermistor 6 and a resistor 10 connected thereto in series while both terminal voltages of the resistor 10 are applied between the base emitters of a transistor amplifier 8 for driving a relay. A temp. abnormality alarm signal 5 is obtained at the operation contact of the relay 9 connected to the collector circuit of the amplifier 8 in series and the current flowing to the thermistor 6 is set so as to be slightly smaller than that for bringing the thermistor 6 to a negative resistance region. By this method, the difference between detection voltages at normal and abnormal times can be made large. |
