Power switch is a device used to control the circuit on and off, the following is a detailed introduction to it:
Working principle
Mechanical switch: by manually operating the mechanical structure, such as pressing the button, flipping the switch handle, etc., the contact is closed or disconnected, so as to achieve the on-off control of the circuit. When the contact is closed, the current can pass through the circuit and the electrical equipment can work normally; When the contact is disconnected, the circuit is cut off, the current cannot pass through, and the electrical equipment stops working.
Electronic switch: The use of electronic components (such as transistors, Fets, etc.) on and off characteristics to control the circuit on and off. Take the transistor as an example, by controlling the voltage or current of the base (or gate), the transistor is in a saturated on-state (equivalent to the switch is closed) or a cut-off state (equivalent to the switch is off), so as to achieve the control of the current in the circuit.
Common type
By operation
Button switch: by pressing the button to achieve the circuit on and off, generally divided into normally open button, normally closed button and composite button. When the normally open button is not pressed, the contact is disconnected, and the contact is closed after pressing; Normally closed button is on the contrary, the contact is closed when not pressed, and the contact is disconnected after pressing; The composite button has both normally open and normally closed contacts. It is often used in the start and stop control of various electrical equipment, such as the power switch of the computer host, the call button of the elevator, etc.
Toggle switch: By toggle the switch handle to switch the circuit state, there are two or more positions, can achieve different circuit switching or on-off control. Common in some small electronic devices, such as flashlights, radios, etc., used to control the power switch or mode switching of the device.
Rotary switch: By rotating operation to change the circuit connection state, usually has multiple gears, can be used to select different functions or adjust parameters. Such as some audio equipment on the volume adjustment switch, channel selection switch and so on.
By function
Single-pole switch: can only control the on-off of a circuit, such as the common wall switch used to control a lamp, is usually a single-pole switch.
Bipolar switch: can control the on-off of two circuits at the same time, often used in the circuit that needs to control the live line and the neutral line at the same time, to ensure that when the switch is disconnected, the electrical equipment is completely isolated from the power supply and improve safety.
Leakage protection switch: In addition to the on-off control function of ordinary switches, it can also detect the leakage current in the circuit. When the circuit leakage occurs, and the leakage current reaches a certain value, the leakage protection switch will automatically cut off the circuit to prevent the occurrence of accidents such as electric shock and electrical fire, which is widely used in electrical lines in homes, shopping malls and other places.
