| 摘要 |
PURPOSE:To exercise high-precision, high-stability temperature control by leading a sensor signal to the earch during a positive-half-cycle period when the sensor signal has distortion. CONSTITUTION:A positive-cycle-pulse generating circuit 19 which generates a pulse Vp during a positive-half-cycle period and a grounding circuit for a sensor signal which is turned on by the pulse Vp and composed of a switching transistor (TR) 20 are added. A TR18 normally turns off and the collector current of the TR8 is integrated in a capacitor 10, but when the circuit 19 generates the pulse Vp, the TR20 turns on to ground the collector current of the TR8. Namely, a sensor signal is grounded during the positive-half-cycle period when the sensor signal has distortion. Consequently, an accurate temperature signal irrelevant to whether a heater is powered up or not is obtained, and thus high- precision, high-stability temperature control is exercised. |
