What is a mercury switch?

A mercury switch is an electrical switch that operates based on the movement of mercury. It consists of a small glass or plastic tube, with a drop of mercury inside. When the switch is tilted or moved in a particular direction, the mercury moves to one end of the tube, completing an electrical circuit and turning on a device or appliance.

Mercury switches were widely used in older thermostats, automotive tilt sensors, and other applications, but have largely been replaced by electronic switches due to concerns about the toxicity of mercury. In addition to being harmful to the environment and human health, mercury can also be dangerous if the switch is broken or if the mercury is inhaled or ingested.

Due to these concerns, many countries have banned the use of mercury switches or placed restrictions on their use in certain applications. However, some specialized industries, such as aerospace and nuclear power, still use mercury switches because they are reliable and withstand harsh environmental conditions.