Abstract: The tester does not require any external power source as it derives its energy from the pulse being measured. It includes circuitry which produces a signal proportional to the energy without directly calculating the energy. This is accomplished by generating a current portional to E.sup.2 with a diode network and then integrating the current in a capacitor thus indirectly measuring the true energy. The results are read directly upon a linear meter or can be connected to an oscilloscope or the like for inspection or recording. A bridge rectifier can be used so that the circuit is responsive to both polarities of input pulse or it can be made responsive only to the unipolar signal.