How Smoke Detectors Work

A very simple device that has saved thousands of lives is the smoke detector. It also probably goes off every time the cook of the house makes pancakes or grilled cheese sandwiches.

Diagram Showing How Smoke Detectors Work

A smoke detector is basically just an electrical circuit that gets interrupted or at least disturbed by particles. The circuit runs through a chamber where there is a very small separation between two electrodes. The electricity "jumps" across this open space. The current goes around and around. Meanwhile the microchip monitors the flow of electricity. As long as the flow is constant it does nothing.

It has been said that where there is smoke there is fire. It is even more true that where there is fire there is smoke. A fire sends little particles into the air. When these particles reach the smoke detector, they go through the little chamber where the electrons are flying from one electrode to the other. The smoke particles interfere with this flow enough to alert the microchip. The microchip is programmed to send a signal to the alarm. The alarm sounds and either someone takes a frying pan off the stove and silences the alarm or everyone exits the house in an orderly fashion and waits for the fire department to handle the blaze.

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