Operating Principles
All objects above absolute zero emit heat energy in the form of optical radiation (light). Usually this light is invisible to the human eye because body temperature radiates at infrared wavelengths, but it can be detected by electronic devices designed for such a purpose.
The term passive in this instance refers to the fact that PIR devices do not generate or radiate any energy for detection purposes. They work entirely by detecting the energy given off by other objects.
Read more about this topic: Passive Infrared Sensor
Famous quotes containing the words operating and/or principles:
“I love meetings with suits. I live for meetings with suits. I love them because I know they had a really boring week and I walk in there with my orange velvet leggings and drop popcorn in my cleavage and then fish it out and eat it. I like that. I know I’m entertaining them and I know that they know. Obviously, the best meetings are with suits that are intelligent, because then things are operating on a whole other level.”
—Madonna [Madonna Louise Ciccione] (b. 1959)
“The chief lesson of the Depression should never be forgotten. Even our liberty-loving American people will sacrifice their freedom and their democratic principles if their security and their very lives are threatened by another breakdown of our free enterprise system. We can no more afford another general depression than we can afford another total war, if democracy is to survive.”
—Agnes E. Meyer (1887–1970)