[en] The spectrometer comprises an extraction grid and a suppressor grid in its bottom part, and a detector electrode and a trap electrode in the upper part. All grids are mechanically interconnected and electrically insulated one from the other. The spectrometer features a high and constant signal-to-noise ratio, thanks to which the absolute accuracy of voltage measurement is as high as 99%. The spectrometer is conceived as an auxiliary equipment of an electron microscope, being mounted under its last lens. The device enables voltage to be measured on parts with micrometer dimensions, e.g., during performance testing of integrated circuits. The spectrometer can also be employed for experimental measurement of some emission characteristics of materials during their interaction with an electron beam. (M.D.). 2 figs