Engineering & Technology


Tilt Switches

A tilt switch has two contacts within a glass bulb or metal container. A small ball bearing or ball of mercury metal completes the circuit when it is tilted. Mercury is no longer used though since it is highly toxic.

Some motorbike alarms have tilt switches to trigger the alarm when the bike is moved.

Twp types of tilt switch
A tilt switch in action
Reed Switches

Reed switches consist of switch contacts enclosed within a glass tube. Because the contacts are made of iron, when a magnet is placed close to them, one of the contacts moves to touch the other.

One application is in security systems where they are used to detect if a door has been opened.

A glass reed switch and symbol
Action of reed switch in presence of magnet