| 摘要 |
PURPOSE:To detect a temperature accurately in a low-temperature atmosphere by providing a switch between two temperature detecting elements and two resistances which constitute a bridge and supplying power only to temperature detecting elements for a prescribed time after feed start. CONSTITUTION:Temperature detecting elements 37a and 37b and resistances 38 and 39 are connected by a switch 40a to constitute a bridge circuit 36. When a power source is turned on, a DC voltage is supplied to the bridge circuit 36 and a timer circuit 42 from a constant voltage circuit 34. The timer circuit 42 excites a relay coil 40 a prescribed time after feeding of the DC voltage. The coil 40 makes a switch 40a. Consequently, a current is flowed only to elements 37a and 37b for a prescribed time after feeding of the DC voltage, and self-heating is performed. When the switch 40a is made, the temperature is detected by the bridge circuit 36 and an amplifier 41. |
