Frequency Converter

Frequency measures how often a periodic event occurs per unit time. The SI unit is the Hertz (Hz), equal to one cycle per second, named after Heinrich Hertz who first demonstrated electromagnetic waves. The metric prefixes scale Hertz for different applications: kilohertz (kHz, thousands of Hz) for audio frequencies and AM radio, megahertz (MHz, millions of Hz) for FM radio and older processors, and gigahertz (GHz, billions of Hz) for modern computer processors, Wi-Fi, and microwave communications. A typical smartphone processor runs at 2-3 GHz, executing billions of clock cycles per second. RPM (revolutions per minute) measures rotational speed. Car engines idle at about 600-900 RPM, hard drives spin at 5400-7200 RPM, and jet engine turbines reach 10,000-40,000 RPM. To convert RPM to Hertz, divide by 60 (since there are 60 seconds per minute). One RPM equals 1/60 Hz. Radians per second (rad/s) is the angular frequency, often denoted omega. It relates to Hertz by omega = 2*pi*f, where f is frequency in Hz. Angular frequency is the natural unit for physics equations involving rotation and oscillation: the simple harmonic oscillator equation uses omega, not Hz. Control systems engineers work primarily in rad/s because transfer functions are expressed in the Laplace domain using omega. Frequency and period are reciprocals: T = 1/f. A 1 kHz signal has a period of 1 millisecond. This relationship is fundamental in timing applications, digital communications, and waveform analysis. The audible frequency range for humans is approximately 20 Hz to 20 kHz, though this decreases with age. Middle C on a piano is approximately 261.63 Hz. The electromagnetic spectrum extends from extremely low frequencies (3-30 Hz) through radio, microwave, infrared, visible light (430-770 THz), ultraviolet, X-rays, to gamma rays (above 10^19 Hz).