What Are They, And How Do They Work?


The forehead thermometer uses an infrared sensor to pick up the infrared radiation produced by the body. Although infrared light is invisible, one can feel heat.

A person's temperature can be measured with a forehead thermometer held a few centimeters from the center of his forehead, just above his eyebrows. Precise positioning will depend on the manufacturer's instructions.

The lens inside the thermometer focuses the infrared radiation emitted by a person onto a thermonuclear reactor, a small electronic device that converts infrared radiation into heat and then into electricity.

The thermometer takes this electrical reading and displays the results on the screen of the thermometer.

It only takes a few seconds to take your temperature with a thermometer on your forehead.