The current transients arising after the sudden heating of an electrode by high-power laser irradiation have been studied. The method has been applied to a Au(111) single-crystal electrode in contact with perchloric and sulfuric acid solutions. The current transient can be explained as due to the recovery of the double layer capacity after its decrease due to the sudden rise of the temperature. It has been found that there is a correlation between the sign of the current transient and the sign of the double layer charge, and there is a coincidence between the potential where the transient vanishes and the potential of zero charge. This allows its use as a general method for determination of the potential of zero charge of solid electrodes.