An Oscillograph for Ten Thousand Cycles

Efforts to extend the frequency range of oscillographs have, for the most part, been directed toward increasing the natural frequency of the vibrating element, which has formed the upper limit of the useful range. This paper describes a new method of attack which consists in employing a vibrator strung to only a moderately high natural frequency, and in equalizing the response of the string by electrical circuits both up to and beyond the fundamental resonance frequency. Employing this method of equalization, a galvanometer element has been developed for the rapid record oscillograph which uses strings stretched to a natural frequency of 4500 c.p.s., and equalized to from ten to twelve thousand cycles. The paper concludes with a description of such a modified rapid record oscillograph and with an oscillogram illustrating its use.