The paper proposes and experimentally demonstrates a method for estimating the coefficient of electron extraction from a plasma emitter based on a low-pressure arc discharge with layered/grid stabilization of the emission plasma boundary. The method is based on the exclusion of the emission current from the total current in the accelerating gap by "sharp" switching off the arc discharge current. The condition for the applicability of the method is an insignificant change in the concentration of the anode plasma during the cutoff of the discharge current pulse. The preliminary data obtained testify in favor of a change in the electron extraction coefficient by up to 20% during a discharge current pulse with a duration of 150 μs.