What’s the Story Behind Unit Hertz in High Tech Tools?

Apr 8, 2019 by

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Whether in mobile phones, computers, televisions or countless other modern electronics, we typically use hertz as a unit of measurement. The term replaced the earlier unit of “cps,” though it is still expressed in cycles per second – the cycles usually referring to the cycle of a sound wave, electromagnetic waves or alternating currents. It was first proposed as the term in the 1920s in order to honour the work and the discoveries made by Heinrich and it was adopted on a wider scale in 1933.

Who Was Heinrich Hertz?

The man who lent his name to the unit of frequency lived between 1857 and 1894 and is best known for discovering radio waves and confirming the theory of electromagnetism first theorised by James Clerk Maxwell. The firstborn son of a German senator and physician, Heinrich was raised in the Lutheran faith, but began to shift away from his religious upbringing at school, where he discovered a natural proclivity for academics. After a year of compulsory army service, he returned to his studies in Munich, where he decided to become a physicist.

Under the tutelage of the physicist Hermann von Helmholtz, Hertz eventually won a gold medal for answering the question of whether or not electric current has mass and was also able to prove Maxwell’s theory for the Berlin Academy. It wasn’t until 1886, however, that he made the discovery that would make his name, when he first generated radio waves and changed the world forever.

How to Calculate Hertz

Calculating a frequency in Hertz essentially involves choosing the unit of time and counting the number of cycles within that period, with 1 Hertz equalling one cycle/sec. Depending on what you’re measuring, you’ll use a number of prefixes such as kilohertz and gigahertz, with the former equating 1,000 and the latter meaning 1 million.

For reference, in music, most instruments are tuned to the standard of 440Hz as the A above middle C, with a typical piano keyboard reaching from 55Hz all the way to over 4,000. The average human hearing range is between 20 and 20,000Hz, but as we age, the frequencies we can hear diminish. Hertz can be measured by various pieces of equipment, with companies such as MCS Test offering a variety of EMC, Wireless, Avionic and Mobile Radio Test Equipment across multiple standards.

Common Hertz

  • The typical household electrical supply in the US is 60Hz, whilst in Europe, it’s 50Hz.
  • Broadcast transmissions are generally expressed in kilohertz and megahertz.
  • Most Wi-Fi networks operate in either 2.4GHz or 5GHz frequency bands, because they are the frequency ranges most commonly open in most countries. A Bluetooth connection also uses 2.4GHz.
  • Old-school cordless phones operated in the 900MHz frequency range.
  • Most modern audio is encoded at 44.1KHz.
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