A photocell is provided to detect the rejected bags .
光电池可以用来发现被拒绝的袋。
We must use photocell as detectors .
我们必须用光电管作为探测器。
Measuring methods of photocell - rise time and fall time .
光电池测量方法上升时间,下降时间。
The registers and players all use some kind of photocell , but what is more interesting from an einsteinian perspective is the red beam of coherent light they shoot .
