Electronic switches are devices that can interrupt the flow of a circuit. Many electronic switches are binary devices that are either closed to allow the current to pass through the circuit or they are open, which breaks the flow. Other switches have multiple closed positions that allow varying currents to pass through, altering the output.
Electronic switches are categorized by various factors including their actuator, which is a mechanism that applies force to the switch’s contacts. Switches generally consist of conducting material, wires, terminals and actuators housed in a protective casing; these components vary in quantity and arrangement, but they are similar in that they can complete a circuit by allowing an electrical current to flow through them. Complex switches turn on or off when a light or magnetic field is sensed, while simple switches require physical contact with the conductors and actuator.
There are many different kinds of electronic switches. One main differentiation is between single pole (SP) and double pole (DP). SP switches have two contacts that enable the circuit to be either open or closed. DP switches have two closed positions and one for an open circuit (that is, two “on” positions with one “off”). Electronic switches are used in every device with the ability to power on or turn off. Computers, radios, microwaves, headlights, televisions and toasters are just a few examples of devices in which electronic switches are used.
The actuator is an important part of the switch; it determines the arrangement of other internal components. Electrical switch actuators include plungers, rockers, push buttons, dials or toggles; these actuators are used in many different arrangements. Toggle switches are switches with an angled lever that rests in one of at least two positions. An internal spring mechanism ensures that it returns to a definite position. Push button switches have two positions: depressed and released.
Some latch until pulled out while others have a spring that returns the actuator to its original position. Selector switches have a knob or lever that can be rotated to select at least two positions. Joystick switches have a lever with at least two axes of motion that control the circuit based on which way it is turned and how far it is pushed.
Some switches are designed to be operated by a machine’s movement; these switches are called limit switches because they limit the motion of a machine by turning off the power if the machine moves too far away from the switch. Proximity switches are able to sense either approaching metallic objects through a disruption in its magnetic field or through a change in light as interpreted by its photocell.