| 摘要 |
PROBLEM TO BE SOLVED: To maintain a sensing part at a constant high temperature by a main heater and an auxiliary heater. SOLUTION: The circuit includes a sensing part which can be maintained at a high temperature, e.g. 400 deg.C, and a thermally conductive insulating plate or film with a main heater 30 and an auxiliary heater 32 arranged adjacent to each other. A bridge circuit 18 has the auxiliary heater 32 in one arm and a first resistor 12, a second resistor 14 and a third resistor 16 in the other three arms. A power supply circuit has a voltage follower 20 feeding a voltage to the main heater 30 and an amplifier 24 which has an inverting input terminal thereof connected to a series connection point of the first resistor 12 and auxiliary heater 32, a non-inverting input terminal connected to a series connection point of the second resistor 14 and third resistor 16, and an output terminal connected to a control input terminal of the voltage follower 20. |
