What is a tact switch?How to choose a tact switch?

Publish Time:2022-10-09 Author:jiaxi Views:346

What is a tact switch?

A tact switch is widely used in people's daily life, such as audio and video products, computer keyboards, household appliances, remote controls, etc. When it comes to these supplies, everyone knows what a tact switch is. The following describes It is the detailed knowledge of the tact switch, so that everyone has a better understanding of the tact switch, and it is more convenient and quick to use.

Tact switch, as the name implies, is an electronic switch, which belongs to the category of electronic components. In addition, the tact switch is also called a key switch, which first appeared in Japan as a sensitive switch. The function of the pressure switch in the operating direction is closed and turned on. When the pressure is removed, the switch will be turned off. Its internal structure is realized by the change of the force of the metal shrapnel. The tact switch has a small contact resistance load and accurate operating force error. The advantages of diversified specifications, etc., have been widely used in electronic equipment and white goods. For example: how to connect the shadow tact switch On. When the hand is released, the switch is disconnected, and its internal structure is realized by the force of the metal shrapnel.


How to choose a tact switch

A good tact switch is also very important for the life of the entire product. For example, computer keyboards, remote controls, etc. If it is an inferior tact switch, the metal shrapnel will be fatigued and lost after frequent pressing. Elasticity fails. Therefore, the selection of tact switches is very important. How to choose tact switches? 

1.The first is the pin base material, the pin base material of the tact switch is brass or phosphor bronze (low-grade iron), in order to reduce the contact resistance, the pins are basically silver-plated, and the silver meets the SO2 gas in the air. It will oxidize and directly affect the solderability and contact resistance of the switch, so high-quality tact switches must first be controlled in place in terms of the thickness of the silver plating on the base material of the pins and the silver plating process

2.The key influencing factor of conduction reliability is the structure of the contact point, because the function of the tact switch is to conduct contact between the contact point and the shrapnel, so the larger the contact surface of the contact point, the better, and the contact surface is determined by the structure.



How to connect the touch switch?

Many people have certain doubts about this. Let’s take a look at what to do and what to pay attention to. The working principle of the tact switch After the 220V alternating current passes through the bulb H and the rectifier full bridge, it becomes a DC pulsating voltage; as a positive The bias voltage is applied to the thyristor VS and R branches. During the day, when the brightness is greater than a certain level, the photodiode D presents a bottom resistance state of ≤1KΩ, which makes the triode V cut off, and its emitter has no current output. VS is blocked because there is no trigger current. At this time, the current flowing through the bulb H is less than or equal to 2.2mA, and the bulb H cannot emit light. The resistor R1 and the Zener diode DW make the V bias of the triode not exceed 6.8V, which protects the triode. Night , When the brightness is less than a certain level, the photodiode D presents a high resistance state of ≥100KΩ, so that the triode V is forward-conducting. it is good