Investigation of the operation speed of AC voltage sensor In the article the AC voltage sensor of industrial frequency – the signal former of the analogue controller with pulse-width modulation which, in its turn, controls the high-frequency electronic pulse AC voltage stabilizer, is considered. It is shown, that the necessary for controller feedback signal in the form of DC voltage can be received by means of the multiphase rectification scheme. The multiphase symmetrical voltage system is formed from a controlled single-phase voltage, using the phase-shifting bridge with several RC-circuits. Speed of such sensor depends on output circuit time lag, i.e., on a smoothing filter time constant. In steady-state modes a variable component of the output signal is governed with output filter condenser capacity and quantity of voltage pulsations on an rectifier schema’s output during controlled voltage period as well. The more the number of pulsations for the period, the less is the capacity of the filter condenser, which limits sensor’s speed with a controlled voltage change. In the work the dependence of a time constant on a quantity of pulsations of the rectified voltage with reference to 1 % and 5 % to pulsations at a output signal of the sensor is received. With help of computer simulation of the changes of voltage amplitude, sensor’s processing speed in an idling mode is estimated. The calculation methods were developed for phase-shifting circuits during the work of a sensor with variable loading. As an example the results of tests of speed of the loaded sensor with three-phase bridge rectifier scheme are also received.