A Thermionic Voltmeter Method for the Harmonic Analysis of Electrical Waves

A thermionic voltmeter method for the harmonic analysis of complex electrical waves is given. The sensitivity and accuracy of the method are tested by measuring wave forms of known harmonic content. Accuracy greater than 1 per cent (referred to the harmonic) for a harmonic of 10 per cent of the fundamental, and greater than 3 per cent accuracy for a 1 per cent harmonic may be obtained. Examples with oscillograms of various applications of the method are given. Sources of error and limits of sensitivity are discussed.