频闪观测器（Stroboscope）又称同步定时仪，可测量反复运动所需的时间。

频闪观测器是一个可以转动的圆盘，圆盘上有狭缝，能发出脉冲光。频闪观测器大多用来量度水波、脑波的频率。

A flashtube, also called a flashlamp, is an electric arc lamp designed to produce extremely intense, incoherent, full-spectrum white light for very short durations. Flashtubes are made of a length of glass tubing with electrodes at either end and are filled with a gas that, when triggered, ionizes and conducts a high voltage pulse to produce the light. Flashtubes are used mostly for photographic purposes but are also employed in scientific, medical, industrial, and entertainment applications.