A race is timed electronically by a phototimer which is accurate to one hundredth of a second. 径赛采用配有摄影计时器的电子计时,精确到百分之一秒。
Methods To automatically adjust x ray tube voltage of fluoroscopy for image brightness control, to use phototimer for autocontrol of exposure time. 方法自动调整透视管电压以控制图像的亮度;利用光电计时器自动控制曝光时间。