Hertz

One hertz simply means "one per second"; 100 Hz means "one hundred per second", and so on. The unit may be applied to any periodic event – for example, a clock might be said to tick at 1 Hz.

In older writings, the equivalent unit cycle per second (cps) is seen.

SI Multiples

1 kilohertz (symbol kHz) = 10³ Hz = 1,000 Hz

1 megahertz (symbol MHz) = 10⁶ Hz = 1,000,000 Hz

1 gigahertz (symbol GHz) = 10⁹ Hz = 1,000,000,000 Hz

1 terahertz (symbol THz) = 10¹² Hz = 1,000,000,000,000 Hz

1 petahertz (symbol PHz) = 10¹⁵ Hz = 1,000,000,000,000,000 Hz

1 exahertz (symbol EHz) = 10¹⁸ Hz = 1,000,000,000,000,000,000 Hz

Examples

• 50 or 60 Hz, electromagnetic – standard AC electric power supplies
• 261.625 Hz, acoustic – the musical note middle C
• 440 Hz, acoustic – concert pitch (A above middle C), used for tuning musical instruments
• 104 kHz, transitions – the clock speed of the first commercially produced microprocessor, the Intel 4004 (1971)
• 1 to 8 MHz, transitions – clock speeds of early home/personal computers (late 1970s, early-to-mid 1980s)
• 88 to 108 MHz, electromagnetic – FM radio broadcasts
• 2.2 GHz, transitions – clock speed of the Pentium 4 microprocessor (2002)
• 460 THz, electromagnetic – red light
• 30 PHz, electromagnetic – x-rays

Referenced By