The vale-maintained tuning-fork as a precision time-standard

Abstract

The system of driving a mechanical oscillator by means of a triode was first described by Eccles (1). As applied to the maintenance of vibration of a tuning-fork, the method possesses very great advantages over any previously arranged electro-mechanical method. The complete absence of any attachments to the vibrator, together with the property of perfect self-starting, enables conditions of steadiness in operation to do realised which would not do otherwise possible. One such tuning-fork in use at the N. P. L. controls a multi-vibrator (2) and so forms the foundation of the radio-frequency standards of the laboratory.