A scheme for measuring voltage peaks

SOME time ago, some of my work called for the accurate measurement of the peak value of voltage waves. The existing schemes for such measurement, based on a rectifier charging a condenser, did not strongly commend themselves for my purposes. Finally, I devised a scheme for measuring voltage peaks that requires only standard apparatus that is easily portable, and that can be carried to any degree of accuracy desired, without especially skillful handling. It can be applied to any periodic voltage, pulsating or alternating. As it is a zero method, it can be used where a method requiring flow of current would introduce serious error.