The application of four foot key switch

Four-foot key switches are widely used. In household appliances, electric fans, microwave ovens, televisions, electronic fat scales, rice cookers and electronic kitchen scales, etc.; monitors, video interphones, etc. in security products; voice recorders, cameras, etc. in computers; medical equipment Call systems, sphygmomanometers, thermometers, etc., massage chairs in fitness equipment, running machines, etc., in these fields, four-foot key switches are involved in applications. In addition, t

Classification：Key switch news

Author: AUGO Electronics

Release date：2022-02-20 18:39:47

Welding with four-pin button open:
1. Adjust the multimeter to the diode
2. First measure any two feet in the four corners to determine which two corners are connected and which two corners are disconnected
3. Press the button and measure any two feet to determine which two corners are connected and which two corners are disconnected
4. Begin to disconnect, press the button and the conductive feet can be used as two corners for welding
According to experience, generally as long as the diagonal can be directly welded.

The picture above is the wiring diagram, pins 1 and 2 are one end, pins 3 and 4 are the other end, and different manufacturers have different markings.
The tact switch is to press to turn on the circuit, the circuit is still connected after the hand is released, and the circuit is disconnected by pressing it again;
Due to the small size of the components and the poor mechanical strength, in order to reliably connect the circuit and reduce the contact resistance, two sets of contacts are used to work in parallel, so there are 4 pins, instead of the relay, one set is normally open contact, the other set is a normally closed contact.
The structure can be distinguished by the resistance file of the multimeter, or the manufacturer's information can be searched by model.
The working principle of key switch is that when the key is pressed, the two patches are close together, that is, It is turned on; when it is released, the patch is separated, that is, disconnected.
Regarding the welding of the switch, it is necessary to confirm the production conditions first. Due to different production conditions, the load applied to the terminal, deformation and deterioration may also occur, so be sure to pay attention to this point when using it. For the influence of thermal stress on the four-pin key switch, it is necessary to make sufficient preparations for confirmation before use; during the second welding process, please wait for the key switch to return to normal temperature after the first welding, and then perform the second welding. If it is heated continuously, the shape of the four-pin key switch will be changed, and the terminals may also loosen and fall off, resulting in reduced electrical characteristics or damage. The resistive load of the four-pin key switch is designed on the premise. When using other loads, please pay attention to confirmation.

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