Sensor Facts for Kids

A CCD (charge-coupled device) has a grid of sensors that react to light.

$Cathode ray diffraction$

A television tube or other CRT (cathode ray tube) detects electrons on its screen.

This photometer measured brightness by comparing shadows

A sensor is a device that measures a physical quantity and converts it into a 'signal' which can be read by an observer or by an instrument. For example, a mercury thermometer converts the measured temperature into the expansion and contraction of a liquid which can be read on a calibrated glass tube. Video cameras and a digital cameras have an image sensor.

There are many different types of sensors. Some are used in everyday objects, and some are separate.

Thermal sensors
Electromagnetic sensors
Mechanical sensors
Motion sensors
Car sensors
Images for kids
See also

Thermal sensors

A sensor that detects temperature. Thermal sensors are in many laptops and computers in order to sound an alarm when a certain temperature has been exceeded.

temperature sensors: thermometers, thermostats
heat sensors: bolometer, calorimeter

Electromagnetic sensors

An electronic device used to measure a physical quantity such as pressure or loudness and convert it into an electronic signal of some kind (e.g. a voltage).

electrical resistance sensors: ohmmeter
electrical voltage sensors: voltmeter
electrical power sensors: watt-hour meter
magnetism sensors: magnetic compass
metal detectors
Radar

This is any thing that can be used to find things like photons, electrons, etc. It can be as simple as a white wall, a sheet of white paper, etc., or as new as a charge-coupled device. When a laser is aimed at a detection screen, a bright spot can be seen on the screen, or when an electron hits the phosphors on another kind of screen, it makes that screen glow.