What is a Mercury Switch?

A mercury switch, also known as a tilt switch, is a type of circuit switch that stores a small drop of mercury in a small container that is connected to the electrode. Most of the container is vacuum or injected with an inert gas.

Mercury switches use the characteristics of good electrical conductivity and fluidity of mercury to open and close the electrical circuit. It is composed of glass tube, mercury, fixed electrode, lead, etc. ^[1]

The shape of the mercury switch can be made into more than 30 types according to the requirements of electrical capacity, operating method and operating angle.

It will be described in terms of contact form, operation method and operation angle.

Mercury switches are based on the movement of mercury enclosed in a glass or metal enclosure to achieve on / off. Therefore, compared with mechanical switches, mercury switches have many characteristics:

Can be used in harsh environmental conditions. Because the mercury switch is sealed, the internal mercury is isolated from the outside, so it can be used in an environment with oil, steam, dust and corrosive gases.

The external force required for switching is small. Mercury is the only one that can stay liquid at room temperature

Mercury switch

Metal has a large surface tension and specific gravity. As long as a slight external force is applied to incline the mercury switch, the mercury can move and the switch can be turned on and off.

Mercury has good conductivity, and the contact resistance between the mercury switch electrodes is generally less than 100m.

The current allowed by the mercury switch depends on the electrode material. The maximum allowable current of the tungsten wire electrode is 10A, while the maximum allowable current of the general alloy wire is generally 1A.

Since the on-off of the mercury switch is determined by mercury gravity, it can work reliably for a long time.

The contact of the electrode is liquid contact without any noise.

Because mercury can flow, as long as the acceleration reaches the set value or higher, the mercury switch can be turned on or off, so it can be used as a vibration sensitive element.

Small volume, various forms, and fully sealed devices.

Simple structure and low price.

High quality, high quality products, suitable for beginners.