转速计，又名转速表、转速仪，是机械行业必备的仪器之一，用来测定电机的转速、线速度或频率。常用于电机、电扇、造纸、塑料、化纤、纺织、汽车、飞机、轮船等制造业。 大多常用的为手持离心式转速计。美国Checkline旗下的转速计一般为数字式，有接触式和非接触式两种测量。非接触式采用光电器件测量，无连接轴，对被测件无任何影响，提高测量精度。

例如Checkline PLT-5000型是一款小型转速计，精准测量转速和表面速度。适用于各种机械和材料处理应用。

PLT-5000运用：

The PLT-5000Pocket Laser Tachometer accurately measures RPM and Surface speed using contact or non-contact measurement techniques. This battery-powered unit is extremely compact for convenient portable use and is supplied in a rugged and attractive plastic housing that is ergonomically designed for optimum comfort.

CHECK-LINE小型激光转速计PLT-5000，拥有非接触式和接触式两种测量技术，可测量转速和表速。机身小巧，携带方便，内置电池。塑料材质外壳结实美观，增加产品使用舒适感。

When measuring RPM in the non-contact measuring mode, the PLT-5000 emits a precision laser beam that is aimed at a small piece of reflective tape, which is affixed to the rotating target.

The PLT-5000 is extremely easy to operate and quickly converts from non-contact operation to contact operation by screwing the contact adapter in place. In addition to RPM's, a wide variety of engineering units for surface speed and length are user-selected via the front panel buttons. Units include; feet per minute, meters/min, yards per minute, inches per minute and more.

A built-in memory stores up to 10 measurements plus minimum, maximum, average and last.

在非接触式模式下，PLT-5000通过发射一条精准的激光束到被测件的反光板上来测量转速。PLT-5000操作起来非常简单，只需要将转换头拧到适当位置就可以快速的进行接触式和非接触式两种模式的转换。还可以通过前面板上的按钮来选择自己想要的测量三个种类，转速，表速和长度。测量单位包括：英尺/分，米/分，码/分，英寸/分等。