EMC Question of the Day: April 1, 2019
Which of the following was the earliest EMC innovation?
- lightning rod
- copper tape
- ground strap
- ferrite beads
Answer
The correct answer is "a." Cave paintings made more than 10,000 years ago depict tall man-made structures being struck by lightning with various animals lying on the ground all around. It is thought that these structures were used primarily for hunting. Prior to a thunderstorm, early humans would bait the area near the structure attracting large animals. Lightning striking the rock structures would cause currents to flow on the surface of the ground around the structure killing any animal on four legs.
Copper tape did not appear on the scene until the bronze age where it was used as bandages to repair wounds caused by bronze-tipped spears (and also the wounds caused by the sharp edges of the copper tape).
Ground straps first appeared in medieval times where they were used to prevent static charge from building up on knights wearing suits of shining armor. In order to achieve the approximately 10,000 ohms of impedance needed to bleed static charge without creating an electrocution hazard, the first ground straps were made from coffee grounds (which is where the term "ground" comes from).
Ferrite beads were developed by the Incas in the early 13th century. Much like today, they were rumored to have magical properties and used to ward off evil spirits.
HAPPY APRIL FOOLS' DAY!
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