外文翻译--基于单片机的学习式倒计时器(编辑修改稿)

外文翻译--基于单片机的学习式倒计时器(编辑修改稿)内容摘要：

untdown, one kind is the news countdown, this kind of countdown in decides cyclical under the signal control pattern to use. What this system design is the study type countdown. This system has the following characteristic:① The design is the independent module, uses studies independently the type working, but adapts the streettraffic control lights time change automatically。 ②The work power source is from the streettraffic control lights, does not need another external connection power line, is advantageous for the installment。 ③ Has many kinds of display modes, the system has 99 s,40 s,20 s,10 the s countdown pattern to be possible to supply the choice. The system installation is flexible, the modulation, the structurization, the extension are good, the movement is safely stable, is highly effective. 2 system system design and the hardware circuit countdown system (may also use at89S series) including the STC10F04XE monolithic integrated circuit, the eliminator supply electric circuit, to examine the electric circuit, the watchdog electric circuit, the driving circuit, the LED display circuit and so on. power circuit this countdown takes the electricity from the signal light, the signal lamp voltage is directly 220 V, after 18 V transformer voltage droppings the rectification bridge has given 7805, for monolithic integrated circuit use. Because has red, yellow, the green 3 kind of signal lights, altogether has used 3 18 V transformers, from red, green, the yellow light takes the electricity separately. examine the electric circuit in the study type countdown electric circuit, must the realtime examination traffic light time. Uses the light pair examination in here. When has the signal input, the light pair TIL117 5 feet (C) outputs for the low level signal, examines the low level through the monolithic integrated。