What is the function of tapping the pin on the switch

 

 

What is the function of tapping the pin on the switch? Let's reveal the secret today.

 

The function of touch switch is divided into two types: one is normally open, the other is normally closed. The most common type is the normally open type. The normally open type refers to that the circuit is generally disconnected. Press the key handle lightly to touch the spring piece and the shot point of the base. At this time, the switch is regarded as on. When the key handle is released, the spring piece and the shot point are separated. At this time, the switch is regarded as separated, and the product performance is OK. When the line is disconnected, the resistance of the two circuits is 30mohm. When the switch is on, the contact resistance of the two circuits is 0. At this time, the switch performance is very good. Normally closed type is relatively rare, because it is not in line with the conventional product design. Normally closed type means that the switch is on under normal conditions, and the circuit and function are disconnected when the switch is triggered. The resistance value of this kind of switch is opposite to the normally open one, so it is generally not recommended. The figure below shows the normally open light touch switch:

 

Whether it is normally open or normally closed, the light touch switch must be composed of more than two pins, so as to form a group of switch functions, which are normally two pins, four pins and five pins. Why is there a five pin switch? Because the fifth foot is used for grounding, what is the grounding foot used for? I think we all know. Of course, there are three feet. Generally, there are more side pressure on the three feet. The third foot is designed for fixation, so you can rest assured to use it and press hard. The figure below shows us a two pin circuit at a glance. Let me explain how the four pins of the tap switch are connected! Normally, 1 and 2 are a group of conduction, 3 and 4 are a group of conduction. When the switch is triggered, 1 and 3 are a group, and 2 and 4 are a group. It is right to design the function of the switch in this way. The following figure shows the circuit diagram and circuit diagram