通用热电偶温控仪的设计

仪器采用了４ 位半 Ａ／ Ｄ 转换器７１３５， 提高了测温精度．又采用了单结晶体管振荡器，其触发脉冲的移相角 α由控温电压控制， 继而调节可控硅的导通角，使得温度升高接近恒温温度时，电热丝两端的加热电压也逐渐减少到零，因而消除了热惯性，提高了控温精度．该仪器通用性强，对 Ｅ 型、 Ｊ型、 Ｋ 型热电偶均能适用

T H E D E S I G N O F C U R R E N T T H E R M O C O U P L E T H E R M O S T A T I N S T R U M E N T

Adopting 4 digit half A/ D converter 7135, therm om etrical precision of the presentinstrum ent w as raised. Unit function transistor oscillation frequency w as controlled by therm ostatvoltage and continuity angle of controlled silicon w as adjusted. W hen the tem perature raised closeto therm ostatic tem perature, tw o term inalheating voltage ofheating w ire can decrease gradudly tozero and rem ove hot inertial, the precision of tem perature control w as im proved. The instrum entis of high versatility and can be used in m odle E, m odel Jand m odle K therm ocouple.