Copper‐coated ZnS : Mn powdered phosphors which can be excited with dc field were prepared and time responses of electroluminescence to unidirectional rectangular voltage pulses were studied at room temperature. Over the manganese concentration range studied (5×10−4−8×10−3g/g Mn) emission decay time was found to be nearly proportional to the average nearest distance of Mn2+to Mn2+luminescent centers. An electroluminescent panel using the phosphor with 1×10−3g/g Mn was most efficient under the pulsed voltage which has pulse width of 120 &mgr;s and repitition rate of 60 Hz.