Frequency Meter

Tesla's frequency meter, patented in 1922 under U.S. Patent 1,402,025, utilized electromechanical resonance to precisely measure periodic electrical oscillations or frequencies. Building on synchronous motor principles, the device employed rotating or reciprocating elements tuned to vibrate or synchronize at specific rates, indicating frequency via scales or indicators. This allowed accurate determination in alternating current systems, essential for tuning circuits and power synchronization.

Developed later in Tesla's career with Waltham Watch Company, it supported wireless and high-frequency work. Historically, it aided radio development and grid stability. Modern frequency analyzers and counters build on resonant measurement, vital in electronics, telecommunications, and power monitoring for signal integrity.