轉速計，又名轉速表、轉速儀，是機械行業的儀器之一，用來測定電機的轉速、線速度或頻率。常用于電機、電扇、造紙、塑料、化纖、紡織、汽車、飛機、輪船等制造業。 大多常用的為手持離心式轉速計。

轉速計，又名轉速表、轉速儀，是機械行業的儀器之一，用來測定電機的轉速、線速度或頻率。常用于電機、電扇、造紙、塑料、化纖、紡織、汽車、飛機、輪船等制造業。 大多常用的為手持離心式轉速計。美國Checkline旗下的轉速計一般為數字式，有接觸式和非接觸式兩種測量。非接觸式采用光電器件測量，無連接軸，對被測件無任何影響，提高測量精度。

例如Checkline DT-2100型是一款接觸式&非接觸式轉速計，集成了數據采集，USB輸出和可編程拓展三大功能。

The Check-Line DT-2100 is an advanced combination contact / non-contact hand-held tachometer. The DT-2100 features data-logging, USB output and a programmable scaling feature to offset RPM according to application variables. It features a backlit LED Display with upper/lower limit icons and a unique X-Y Graphic mode. Additional display modes unique to the DT-2100 is the "Needle Sweep" and Bar Graph" offers the user a choice of how to view the data. The display can also be inverted to optimize the viewing angle.

In non-contact mode the tachometer measures RPM up to 99,999 RPM at distances up to 13 feet or 500 cm. The DT-2100 can also measure contact RPM, surface speed, or length using the supplied screw-on adapter.

Data logging can be set for single point or continuous logging. Single data points as well as statistics (Max, Min, Average) can be stored in the built-in memory and recalled to the display. Often users need to adjust machinery during testing, with the DT-2100 you can mount it on a tripod, select continuous logging and adjust machinery as necessary. After the test, you can easily review the data on the DT-2100's display or download to a computer using the optional PC Software.

The Checkline DT-2100 is supplied as a complete kit with 2 cone tip adapters, funnel tip adapter, shaft extension, 6 inch circumference surface speed wheel, reflective tape, 2 AA batteries ... all supplied in a foam-fitted carrying case. An NIST-Traceable Calibration Certification is optionally available.