Use of the time‐of‐flight (TOF) technique in molecular beam applications is reviewed. If the peak signal height and the hydrodynamic flow time are used as the normalization quantities, then a convenient dimensionless TOF signal is obtained in a double‐convolutional integral form which involves threedimensionless functions: the molecular beam speed distribution function, the chopper gate function, and thedynamic function of the detector and its electronics. The latter two functions are characterized,respectively, by the dimensionless characteristic timesT˜and &tgr;˜e. Numerical examples demonstratedistortions of TOF signals caused by these characteristic times and errors made in analyzing TOF signalswhen not taking into account the effects ofT˜and &tgr;˜e. The orders of magnitudes ofT˜and &tgr;˜eare notnegligible; therefore, their effects should be treated in TOF signal data reductions.