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 connected to the electrode. Most of the container is filled with an inert gas or a vacuum.

working principle:Because of gravity, the mercury and water droplets will flow with the lower part of the container. If you touch two electrodes at the same time, the switch will close the circuit and open the switch.

The shape of the container will also affect the conditions under which mercury and water droplets contact the electrode. For example, the post bomb will use an inverted V shape, so that the recipient can tilt the post without knowing it, close the circuit, brake the explosion, but deliver People (or parcel carriers or makers) will not.

Caution: Mercury is toxic to human body and the environment, so when using the mercury switch, you must be careful to avoid breakage; when it is no longer used, it should be handled properly.

Specific samples:(a) The mercury switch enclosed in a glass case is also the most commonly used form. When this mercury switch is tilted at an operating angle, two electrodes can switch on and off through mercury. Glass tube package The advantage of the type mercury switch is that it can be observed from the outside, and the disadvantage is that it is easily broken.

In order to prevent the glass-enclosed mercury switch from breaking easily, a structure with a plastic protective shell has been designed.

(c) is a metal case mercury switch, the metal case itself is an electrode.

Features:Mercury switches are based on the movement of mercury enclosed in glass or metal shells to achieve switch on and off. Therefore, compared with mechanical switches, mercury switches have many characteristics:

① 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.

② The external force required for continuity is small. Mercury is the only metal that can maintain liquidity at normal temperature. Its surface tension and specific gravity are both large. 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.

③ Mercury has good conductivity, and the contact resistance between the mercury switch electrodes is generally less than 100mΩ.

④ 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.

⑤ Since the on-off of the mercury switch is determined by the gravity of mercury, it can work reliably for a long time.

⑥ The contact of the electrode is liquid contact without any noise.

⑦Because mercury can flow, as long as the acceleration reaches above the set value, the mercury switch can be turned on or off, so it can be used as a vibration sensitive element.

⑧Small volume, various forms, and fully sealed devices.

⑨Simple structure and low price.

Difference between mercury switch and vibration switch:1. All materials of ball switches can meet environmental protection requirements, but mercury switches cannot be achieved due to their own material problems.

2. The ball switch generates a signal due to the conduction of the metal bead and the trigger pin. Because the contact area of the ball and the trigger pin is small and the ball is active, there may be a flash-off phenomenon when conducting. The switch is the contact between the mercury and the trigger terminal. Because the mercury is liquid, the contact surface is stable. Generally speaking, the conduction effect is more stable.

3, the ball switch is a metal housing, the structural strength is better.

Precautions:Mercury is toxic to the human body and the environment, so when you use the mercury switch, you must be careful to avoid breaking it; it should also be handled properly when it is no longer used.