Key switch working principle

The key switch has the advantages of small contact resistance charge, accurate operating force error, diversified specifications, etc. It is widely used in electronic equipment and white goods, such as: video and audio products, digital products, remote controls, communication products, household appliances, security products, toys, computer products, fitness equipment, medical equipment, banknotes, laser pen keys and so on. Because the key switch on the environmental conditions (pressure is less than 2 times the elastic/ambient temperature and humidity conditions and electrical performance) large equipment and high-load buttons are used conductive rubber or pan switch hardware shrapnel directly to replace, such as medical equipment, TV remote control and so on.

About the foot position of the five-pin key switch: two pins are in a group, and the four pins are conductive when the switch body is correctly pressed, and the fifth pin is grounded.

Key switch is the fourth generation of switch products developed with the requirements of the development of electronic technology, the earliest volume is 12mm*12mm, 8mm*8mm two, now 6mm*6mm. Product structure has three kinds of vertical, horizontal and horizontal with ground end, and now there are two types of combined (3M, 4M, SM, 6M, SM) and potentiometer key switch combination, to meet the requirements of various domestic electronic products. The installation size is 6.5mm*4.5mm, 5.5mm*4mm and 6mm*4mm. Foreign countries have 4.5mm*4.5mm small key switch and chip key switch, chip key switch suitable for surface assembly.

Now there is a fifth generation switch - film switch, the function is the same as the key switch, mainly used in electronic instruments and CNC machine tools, but the resistance is large and the feel is poor. In order to overcome the phenomenon of poor hand feel, there is also a contact reed installed in the film switch instead of using a silver layer as a contact point

Key switch is divided into two categories: the use of metal reed as a switch contact piece called key switch, contact resistance is small, feel good, there is a "ticking" crisp sound. Switching habits that use conductive rubber as a contact path are called conductive rubber switches. The switch feels good, but the contact resistance is large, generally 100 to 300n. The structure of the key switch is to move down by the key, so that the contact reed or conductive rubber block contacts the solder and forms a path.

The operating force of the key switch is related to the state of the reed. The initial force is proportional to the compression distance of the reed. When the reed is compressed to 5% to 70%, the operating force suddenly decreases and is accompanied by a "ticking" sound. The rubber switch generally has two structures. The operating force curve varies greatly with the geometry of the rubber block.

Relative humidity :<95%

Rated voltage :12V

Rated current :50mA

Temperature :-25~70℃

The main uses of key switches are color TV, black and white TV, audio equipment, video recorders, cameras, computers, game consoles, fax machines, walkie-talkies, truncheons, machine tool control devices, photocopying, printers, electronic instruments, meters and other household appliances.