countdown timer meaning in Chinese

倒数计时器
延时器

Feasibility of using green traffic light signal countdown timers in hong kong
在本港使用绿色交通灯号时间倒数器的可行性
The system paper generated is through randomly choice question from database , and question database partition by study content . the system also provide countdown timer . candidates are required to submit the paper before timeout or system will submit automatically at time end . score will be calculated at once after submital , and so everything is worked to meet purpose of paperless system
本系统试卷的生成是通过对现有题库内题目的随机抽取而组成的，题库按学习内容的章节划分，系统提供了倒计时功能，考生既可以在规定时间内主动交卷也可在考试时间到后系统自动交卷，交卷后系统立即判卷给出分数，从而达到无纸化考试的目的。