Introduction: Speaking of button (button) switch, I believe that many people will not feel unfamiliar, almost every day will encounter a variety of button switches, such as some household appliances, medical equipment will be available. But if you let its structure, the principle of saying a so, it is estimated that there will be many people will be confused. Today, I will tell you about the structure of the button and the principle of the switch
1. Pushbutton switch principle - Introduction
It is a kind of low-voltage electrical apparatus for issuing instructions in power dragging, and is widely used as a main command apparatus for manually issuing control signals to control contactors, relays, electromagnetic starters and so on in electrical automatic control circuits. Its characteristics are installed in the work in progress in the machine, instrumentation, most of the time is in the initial free state position, only when required under the action of external force to switch to the second state (position), when the external force once removed, due to the role of the spring, the switch will return to the initial position.
Push-button switches can perform basic controls such as start, stop, forward and reverse rotation, variable speed and interlock. Usually each pushbutton switch has two pairs of contacts. Each pair of contacts consists of a normally open contact and a normally closed contact. When the button is pressed, the two pairs of contacts act simultaneously, with the normally closed contact breaking and the normally open contact closing.
2. Button switch principle - structure
Buttons are generally composed of a button cap, a reset spring, a bridge type dynamic contact, a static contact, a pillar linkage and an enclosure.
When the button is not subject to external force (i.e. static), the contacts are divided into start button (i.e. normally open button), stop button (i.e. normally closed button) and composite button (i.e. normally open and normally closed contacts combined into one button). For the start button, the contacts are closed when the button cap is pressed and automatically disconnected and reset when the contacts are released; for the stop button, on the contrary, the contacts are separated when the button cap is pressed and automatically closed and reset when the contacts are released. Compound button is to press the button cap, the bridge dynamic contact downward movement, so that the normally closed contact first disconnected before the normally open contact closed; when the button cap is released, the normally open normally open contact first break reset, the normally open contact then closed reset.
