PURPOSE: To stabilize the temperature of an emitter by controlling a filament current in detecting the temperature of an emitter for thermoelectric field radiation.
CONSTITUTION: The temperature of an emitter is measured with a pyrometer and at the same time the resistance of a filament is measured. On the basis of these values, a resistance value cor responding to a target temperature of the emitter is set in a temperature setting device 7. A filament 1 is heated by a current from a current control circuit 3 and the emitter is heated by the filament. At this time the voltage and current between both terminals of the filament are detected with a voltage detector 4 and a current detector 5, and then the resistance of the filament is obtained with a divider 6. A signal corresponding to the difference between the measured value and the target value of the filament resistance is input to the circuit 3. The circuit 3 thereby controls the emitter temperature to be kept constant by negative feedback.
MIMURA MAKOTO
ADACHI HIROSHI
