Abstract: The temperature control system to be discussed in this paper are characterized by three features:(1) Simplifeid circuitry resulting from the self-exited width eontrol principle, leading to the improvement in accuracy of temperature control;(2) Better temperature drift stability and greater sensitivity of temperature measurement and conversion due to theintegral unit composed of temperature differential measurement,conversion, and amplification components;and (3) Little interference with environmental electromagnetic equipment as a result of the employment of SCR AC Switching and zero-crossing trigger technique, which is an advantage over phasing trigger.