photoelectric tachometer

例句：

1. 1. This photoelectric tachometer is very precise and easy to use.
   这个光电速度计非常精确且易于使用。
2. 2. The engineer used the photoelectric tachometer to measure the speed of the car.
   工程师使用光电速度计测量汽车的速度。
3. 3. The photoelectric tachometer was used to monitor the engine's performance during the test.
   光电速度计被用来监测测试期间发动机的性能。