You might think that a switch is a simple device, yet it comes in an astonishing array of sizes, shapes and forms. According to All About Circuits, a switch is primarily a simple binary device which has two positions – ‘off’ which stops the flow of electrons within the circuit and ‘on’ which restores the flow.
The most commonly available form of switch and the one which most people will automatically imagine if asked to visualise a switch, the rocker switch is often used in the home to operate overhead lights. The shape and design makes it easy to operate, even for people with fairly limited strength and mobility and it is difficult to operate inadvertently, making it ideal for home appliances.
Also commonly found in the home where it is often used as an alternative to the rocker switch in the operation of overhead lights, the toggle switch has a lever mechanism which is pushed up or down. The toggle switch can have two or more positions and in some cases is fitted with a spring which ensures it returns to its original position immediately after use.
As with a joystick controller used for gaming, the joystick switch can be moved in a number of directions in order to enable or disable the current. Depending on the type of switch used, even the amount in which it is moved in any direction can have an effect. Joystick switches can also be utilised by machines which enable or disable the current according to their own movement. In this case they are sometimes also known as ‘limit switches’ as they can limit the movement of a component.
The most basic form of activation of switches is a single press, with another press causing the current to deactivate. That is the essence of a switch. However, there are variations on this model. Some push-button switches operate only momentarily when pressed, while others need to be manually pulled out to switch the current off. The push-button switches come in a huge variety of styles, colors and types. Big wholesalers such as RS Components and Premier Farnell both boast an extensive range. A quick glance at the types available at RS Components’ online switches line will confirm this point.
The reed switch consists of ferrous metal reeds sealed within a glass envelope, which open and close according to the presence of a magnetic field. Formerly used in telephone exchanges, the reed switch is used in a number of electronic systems, such as laptops, security sensors and burglar alarms.
As the name would suggest, a key switch is operated through the insertion of a key, such as the ignition key of a car. Use of a key switch ensures that unregulated personnel cannot use the machine without authorisation, making this type of switch popular in situations where machinery could cause injury to personnel.
Ideal for situations where more than two positions for the switch are required, the rotary switch can accommodate a number of different positions. Uses include equipment such as fans which can be adjusted for several different speeds.
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