| 摘要 |
PURPOSE:To reduce the number of parts, and also to execute exactly a temperature detection and a temperatue control by comparing time data or temperature data of the first time constant circuit and the second time constant circuit, and executing a control so that data of both of them coincide. CONSTITUTION:A microcomputer 9 derives each time data of the first time constant circuit consisting of a transistor TR1, a thermistor 2 and a capacitor 3, and the second time constant circuit consisting of a TR4, a variable resistance 5 and the capacitor 3, by operating a counting circuit 15, and stores it in a memory after executing an operation. Subsequently, a time data TRS is fetched, and TRS+ or -alpha is derived by adding or subtracting a prescribed value alpha. In this state, at the time of a temperature data TRX<TRS-alpha, a control signal Cont2 for dropping a temperature is outputted, and at the time of TRX>TRS+alpha, a control signal Cont1 for raising a temperature is outputted. In case of TRS-alpha <=TRX<TRS+alpha, a measured temperature is equal to a set temperature, therefore, no control signal is outputted. |
