【正文】 外電路控制接線座接線座J2外接電源接線USB電源插座USBJ3電腦供電插座晶體12MJZ單片機(jī)時(shí)鐘振蕩一位共陽數(shù)碼管LED1攝氏溫度符號顯示三位共陽數(shù)碼管LED2溫度值顯示發(fā)光二極管3MMLED3報(bào)警發(fā)光指示兼Q1偏置三極管85504Q1：報(bào)警時(shí)驅(qū)動繼電器；Q2Q3Q4：數(shù)碼管驅(qū)動電阻10KR1單片機(jī)復(fù)位電阻220和470RRRR10R1R1R1R14數(shù)碼管限流，其中R14=470電阻RRRR6三極管基極和溫度傳感器偏置電阻2KR5三極管Q1基極偏置二極管1N4148V1續(xù)流，保護(hù)Q1跳線XX2用元件引腳連繼電器5V2AJDQ　溫度達(dá)到報(bào)警值時(shí)觸點(diǎn)動作PCB板73MMX85MM　　USB電源線60MM　連接電腦USB口五、單元電路設(shè)計(jì)（一）電源部分電路介紹：上圖為電源電路，可以通過U口為電路提供電源，也可通過接線座J2供電，但兩者只能選擇一種為電路供電，不允許同時(shí)供電。 Therefore the tele room belongs to electronic products fever faster, in a short time, room temperature beyond normal temperature, cause the system equipment or produce fire, then paralyzed temperature alarm system will play its function.This paper is to use temperature sensor DS18B20 temperature alarm, automatic measuring current environmental temperature by a single chip microputer AT89C2051 control, and through three seven segment digital pipe display, if the