Rhett Allain Using this relay, you don't have to have a huge current going through both your low-power thingy and your high-power lightbulb. Also, if I wanted to use some microcontroller (like an Arduino or Raspberry Pi) to turn this light on and off, the controller only needs a small output current rather than almost 2 amps.
A Strange Kind of Data Tracks the Weather—and Pirate Ships Spire A group of apes is called a shrewdness; a group of ferrets is called a business; a group of small satellites is called a constellation.
What happens if I hang a neutral object from the string and bring the positively charged PVC pipe? These moving electrons experience an attractive force from the positive charges on the PVC and thus move to the right side of the metal (as seen in the diagram).