Ⅰ. Introduction of the switch
Ⅱ. Description of the switch
Ⅲ. Basic structure of switch
Ⅳ. The main parameters of the switch
Ⅴ. Configurable switch components: lens, body, contacts
Ⅵ. The main material of the switch
Ⅶ. Rated voltage, rated current and rated power of switches
Ⅷ. Push Button Switch - Hall Effect
Ⅸ.Why is it called switch?
X.What is switches with example?
Ⅰ. Introduction of the switch
A switch is an electronic component that can open a circuit, interrupt the current flow, or allow it to flow to other circuits. It can be used in electrical equipment or devices that control the flow of electricity. It allows us to open or close the path of electricity in a circuit, thereby controlling the function of connecting or disconnecting an appliance, device or circuit.
In electrical engineering, a switch is an electrical component that breaks or connects conductive paths in an electrical circuit, interrupting or diverting current from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to an external circuit. Current can pass between a pair of contacts when they are in contact, and no current can flow when the contacts are separated.
A switch may have multiple sets of contacts controlled by the same knob or actuator, and these contacts may operate simultaneously, sequentially, or alternately. Switches can be manually operated, such as light switches or keyboard buttons, or can be used as sensing elements to sense the position, fluid level, pressure or temperature of machine parts, such as thermostats. Many specialized forms exist, such as toggle switches, rotary switches, mercury switches, push button switches, reversing switches, relays, and circuit breakers.
A common use of switches is to control lighting, where multiple switches can be connected in a circuit to easily control light fixtures. Switches in high power circuits must have special construction to prevent damaging arcs when opened.
A switch is an electrical device that can turn on, off or switch circuits. Such as knife switch electromagnetic switch and so on. A flow control device can also be provided on the fluid pipeline. Such as throttle switch, valve switch, etc.
Ⅱ. Description of the switch
The most common form of switch is a manually operated electromechanical device with one or more sets of electrical contacts that are connected to an external circuit. Each set of contacts can be in one of two states: closed meaning the contacts are touching and current can flow between them, or open meaning the contacts are separated and the switch is not conducting. Mechanisms driving the transition between these two states (on or off) are usually of the alternating action or momentary type.
An ideal switch would have no voltage drop when turned off and would have no limitations on voltage or current ratings. It will have zero rise and fall times during state changes and will change state without bouncing between the on and off positions.
A switch can be directly manipulated by a person as a control signal for a system, such as a computer keyboard button, or to control the flow of power in a circuit, such as a light switch. Automatically operated switches can be used to control the movement of a machine, for example, to indicate that a garage door has reached its fully open position or that a machine tool is in position to receive another workpiece.
Switches can also operate with process variables such as pressure, temperature, flow, current, voltage, and force, act as sensors in processes, and are used in automatic control systems. For example, a thermostat is a temperature-operated switch used to control a heating process. A switch operated by another circuit is called a relay.
Large switches can be operated remotely via a motor drive mechanism. Some switches are used to isolate power from the system, provide a visible point of isolation and, if necessary, can be padlocked to prevent accidental operation of the machine during maintenance, or to prevent electrical shock.
Ⅲ. Basic structure of switch
1. The basic structure of the switch is composed of insulating material, case body, joystick, contact, terminal, spring, operation instruction and operation mechanism.
2. In the simplest case, a switch has two conductive pieces, usually metal, called contacts, connected to an external circuit that touch to complete (make) the circuit and separate to open (break) the circuit. When the two contacts are in contact, the current forms a loop, and when the two contacts are not in contact, the current is open. The contact material was chosen for its corrosion resistance, as most metals form insulating oxides that prevent the switch from working. Contact materials are also selected based on electrical conductivity, hardness (wear resistance), mechanical strength, low cost and low toxicity.
3. Sometimes the contacts are plated with anti-corrosion metal. It is generally plated on the contact surface of the contact to avoid affecting its performance due to oxides. Sometimes non-metallic conductive materials, such as conductive plastics, are also used on the contact surface. The formation of an oxide layer on the contact surface, together with surface roughness and contact pressure, determines the contact resistance and wetting current of a mechanical switch. Contacts are sometimes plated with precious metals because of their excellent electrical conductivity and corrosion resistance. They can be designed to wipe against each other to remove any contamination. Sometimes a non-metallic conductor such as conductive plastic is used. To prevent the formation of insulating oxides, a minimum wetting current can be specified for a given switch design.
4. In addition to the contacts in the switch, there will also be movable parts that make the contacts conductive or non-conductive. The switch can be divided into toggle switch, key switch, rocker switch, rotary switch, and side dial switch according to the different movable parts. etc., and the movable part can also be other types of mechanical linkages. There are also non-mechanical circuit conduction switches such as capacitive touch switches, resistive switches, piezoelectric switches, photo-interruption switches, magnetic reed switches, and Hall switches.
Ⅳ. The main parameters of the switch
1. Rated current: refers to the maximum safe current that the switch is allowed to pass when it is turned on. When this value is exceeded, the contacts of the switch will be burned due to excessive current.
2. Rated voltage: It refers to the safe voltage allowed by the switch during normal operation. If the voltage applied to both ends of the switch is greater than this value, it will cause ignition and breakdown between the two contacts.
3. Contact resistance: refers to the resistance value between each pair of contacts when the switch is on. Generally, it is required to be below 0.1-0.5Ω, and the smaller the value, the better.
4. Insulation resistance: refers to the resistance value of the conductor part and the insulation part of the switch, and the insulation resistance value should be above 100MΩ.
5. Withstand voltage: refers to the highest voltage that the switch can withstand between the conductor and the ground.
6. Service life: refers to the number of times the switch can be operated under normal working conditions. The general requirement is around 5000-35000 times.
Ⅴ. Configurable switch components: lens, body, contacts
1. Lens: The main function of the switch assembly lens is to control or change the spread of light. They can refract, reflect or focus light to achieve various optical effects, such as focusing light beams, changing optical paths, adjusting focus, etc. A lens can be concave (focuses light), convex (diverges light), prism (redirects light), etc. Different types of lenses are used for different optical tasks. Switch assembly lenses are usually made of optical grade materials such as glass or plastic to ensure high quality optical transmission.
2. Main body: The main body refers to the core part of a switch device, which usually includes important components such as the operating mechanism, contact parts, connecting terminals, and housing.
Operating mechanism: The operating mechanism is the key part of the main body of the switch assembly. They are responsible for transmitting the operating force to the internal mechanical structure, so that the contact parts are opened or closed.
Contacts: Contacts are the electrical parts in the body of the switch assembly, which can be metal sheets, contacts, or other conductive materials. The contact parts will open or close during the switch operation, so as to control the flow of electric current.
Connection terminal: The connection terminal is the part used to connect the main body of the switch assembly with an external circuit or device. These are usually metal pins or sockets that make electrical connections.
Enclosure: An enclosure is the outer packaging of the switch assembly body to protect the internal mechanical and electrical components from physical damage and the external environment. The housing may also provide a support structure for operating levers, buttons, etc.
3. Contact block: The contact block refers to the electrical components inside the switch, which contact or separate when the switch is operated, thereby controlling the flow of current. The contact block is usually made of metal material, which has good electrical conductivity and durability. The main function of a contact block is to make or break a circuit connection when a switch is operated. When the switch is closed, the contact blocks touch and current flows; when the switch is open, the contact blocks separate and the current is cut off. Contact blocks are usually made of metals with good electrical conductivity, such as silver, copper, gold or their alloys. These materials help ensure a stable electrical connection.
Ⅵ. The main material of the switch
1. Base
Ordinary synthetic plastics: easy to age, flammable, and easy to deform.
Imported reinforced nylon: good insulation, strong rigidity, impact resistance, corrosion
resistance, no deformation under high temperature, ensuring that internal components will never fall off.
Recycled PC material: weak impact resistance, weak heat resistance, easy to deform.
2. Panel
PC material: strong impact resistance, strong heat resistance, high transparency.
ABS: low-grade engineering plastics, easy to change color, low strength.
Electric jade powder: non-flammable, never change color, never wear, strong thermochemical property.
3. Switch mouthpiece
Ordinary reinforced nylon: Over time, there will be astringent belt phenomenon, and the increase of friction will lead to the melting of silver spots and the decrease of carrying capacity.
Self-lubricating type: Nylon, hard material, wear-resistant, self-lubricating, effectively reducing friction.
4. Switch contacts
Silver alloy: low resistance, wear-resistant texture, high melting point, anti-oxidation, comprehensive performance is superior to pure silver.
Pure silver: low resistance, soft texture, low melting point, easy to oxidize, easy to generate arc, burn out wires or switching elements, resulting in poor power supply.
5. Switch current-carrying parts (copper sheet)
Red copper: slightly soft, good elasticity, high conductivity, purple-red.
Brass: It is hard, slightly less elastic, moderately conductive, and bright yellow in color.
Tin phosphor bronze: hard, good elasticity, better conductivity than brass, reddish yellow.
标签：switchs
