| 摘要 |
<p>PURPOSE:To attain the control of temperature with high accuracy by using a means to correct the output of a differential amplifier which is delivered when the coincidence is obtained between a set temperature and a measured temperature to a prescribed level. CONSTITUTION:A constant current circuit 9 is connected to a temperature-sensitve element 3 to obtain the temperature detecting voltage. This detection voltage is supplied to a differential amplifier 10 together with the output of a D/A converter 2 to obtain the differential voltage. This differential voltage is impressed to a comparator 11 to be compared with a sawtooth wave given from a sawtooth wave generator 5 and impressed to a switch element 6 of zero cross. Thus the element 6 is turned on and off to control a heater 7. In this case, a series circuit of resistances R5 and R6 is put between an output terminal of the amplifier 10 and a power supply V. Then the juncture between both resistances is connected to an input terminal of the comparator 11. As a result, the apparent output voltage is impressed at a fixed level although the output voltage of the amplifier 10 is kept at 0. In this way, the temperature control is performed with high accuracy.</p> |
