The development of a computer‐controlled electrochemical impedance spectrometer, based on a Fourier transform algorithm is described. Together with a fast potentiostat the system can be used in the frequency range 1 mHz to 100 kHz. The perturbation signal is a superposition of sine waves with properly chosen frequencies. The overall measurement time is limited only by the lowest frequency in the spectrum and by the data transfer to the computer, thus, time‐resolved impedance spectra measurements can be performed. The principle of operation and technical details are presented and discussed.