The key switch mainly refers to the light touch key switch, also known as the light touch switch. The key switch is an electronic switch, which belongs to the category of electronic components. It first appeared in Japan [called: sensitive switch]. When used, the switch function is closed and turned on by applying pressure to the switch operating direction to meet the conditions of the operating force. When the pressure is on, the switch is disconnected, and its internal structure is realized by the change of the force of the metal shrapnel.
Button switch refers to a switch that uses a button to push the transmission mechanism to make the moving contact and the static contact press on or off and realize the circuit switching. The push button switch is a kind of master electrical appliance with simple structure and wide application. In electrical automatic control circuits, it is used to manually issue control signals to control contactors, relays, electromagnetic starters, etc.
In actual use, in order to prevent misoperation, different marks are usually made on the buttons or painted with different colors to distinguish them, and the colors are red, yellow, blue, white, black, green, etc. Generally red means "stop" or "dangerous" operation; green means "start" or "on". The emergency stop button must be a red mushroom head button. The button must have a metal protective retaining ring, and the retaining ring should be higher than the button cap to prevent accidental touch of the button and cause misoperation. The material of the button plate and button box on which the button is installed must be metal and connected to the general ground bus of the machine.
Most people are probably not very clear about the difference between a key switch and a rotary switch. They only understand it very simply as the difference in appearance. In fact, it is not. There is a very big structural difference between them:
1. The structure of the key switch is divided into two types: with a lock and without a lock. If there is a lock, it will be locked by the itinerary after pressing it, and it must be pressed once before it can be disconnected. On the contrary, no lock means that it is not easy to lock after pressing, and it is disconnected immediately after releasing the hand.
2. The structure of the rotary switch is divided into the following 5 types:
1. Normally closed contact (moving and breaking contact): It refers to the contact in which the fixed contact point and the moving contact point are closed in the initial situation (the household appliance is not subjected to external force or the electromagnetic coil is not connected to the power supply).
2. Normally open contact (moving contact): refers to the contact in which the fixed contact point and the moving contact point are separated in the initial situation (the household appliance is not subjected to external force or the electromagnetic coil is not connected to the power supply).
3. The normally closed (moving off) knob switch is reversed to the normally open knob switch. When it is not pressed, the contact is closed, and the contact is disconnected when it is pressed; when the hand is released, the knob switch has the effect of resetting Lower reset to close. The normally closed button is commonly used to operate the motor to park, also known as the self-reset button.
4. Normally open (moving and closing) rotary switch, when not pressed, the contact is disconnected, when pressed, the contact is closed and connected; when released, the rotary switch is reset and disconnected under the effect of reset and yellow. In the control loop, the normally open button is often used to start the motor, also known as the start button.
5. Composite rotary switch: a rotary switch that combines normally open and normally closed rotary switches, that is, with normally closed contacts and normally open contacts. When not pressed, the normally closed contact is closed and the normally open contact is open. When the button is pressed, the normally closed contact will be disconnected first, and the normally open contact will be closed later, which can be regarded as a locking button; when it is released, the rotary switch will first open the normally open contact under the effect of resetting and popping yellow. The contact is opened, which in turn closes the normally closed contact. Compound keys are used in interlocking control loops.
