This article gives you an overview of the switches by showing what they are, commonly used types, and the different uses.
Switches are electromechanical devices that allow users to interact with electronic circuits and are used in various applications, including radio buttons, circuit reset, and general inputs.
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Tactile switches are the most common mechanical switches that do not use PCB pins. They come in all shapes and sizes, are available in through-hole and SMD housings, and are generally very inexpensive.
One feature that makes a tactile switch desirable is clicking feedback, so the user knows when it was pressed correctly.
Single Pole Dual Throw Switch
Single Pole DIP switches, commonly known as SPDT switches, are simply one input and two output switches that allow an electrical switch to connect and isolate two separate wires from a common wire. SPDT switches are less common these days. But in the past, they were very common in designs that required a switch to isolate the power source from the circuit (such as a battery). They go through holes and SMDs, and their packaging is highly varied as well. Switches are that they are usually fixed in any position and usually only have three contacts (sometimes there can be four).
Miniature Snap-Action Switch
Miniature action switches are often called microswitches after the company invented them, also known as microswitches.
They are functionally similar to SPDTs and tactile switches in that they can electrically isolate conductors and have a click function similar to touch. However, quick action switches have a lever that allows them to be shifted with very little effort.
Momentary switches are often found in difficult and complex situations where small movements need to be detected; for example, they are commonly used in numerical control machines as travel switches to prevent the CNC machine from going off-axis, in safety devices such as microwave doors and sensitive machines. with a different movement.
Dual Inline Packet (DIP) switches, as the name suggests, consist of multiple STSP switches housed in a single DIP. Each switch is electrically isolated from the others and is not intended to be permanently adjusted.
These switches are available with through-hole and SMD types and are also available with a protruding button (easier to adjust) and a switch head located in the slot to prevent accidental changes.
DIP switches are usually found on microcontroller boards, where they are used to change the board’s functionality or provide some form of basic configuration. Although they are still in production, they are not often found in modern designs because two-wire EEPROMs are cheaper and can store many kilobytes of configuration data.
Reed switches, while a bit outdated, are very useful and are controlled by a magnetic field. A reed switch consists of a tiny box with two strips of ferromagnetic contacts that close when a magnetic field is present.
These types of switches are incredibly useful in situations where there cannot be physical contact between two objects, such as doors and barriers. The gate or the barrier is equipped with a magnet that causes the reed switch to open or close when it is opened or closed.
Reed switches often consist of a glass vial filled with an inert gas that prevents the contacts from oxidising. A plastic box can surround the glass tube itself.
Push Button Switch
Pushbutton switches are switches that have an internal spring mechanism that prevents the switch from engaging when pressed and bouncing when released.
These switches can be made to make or break electrical contact and are helpful in various applications, including option buttons on an interface such as emergency stop buttons or game controllers.
One of the problems with some push buttons is that they do not provide tactile feedback, so it can be difficult to tell if they have been pushed correctly.
Metal Cap PCB Contact Switch
Metal cap circuit board contact switches differ from previous switches in that, instead of a rubber membrane with carbon contact pads, they use a metal dome that provides a click effect when pressed or released.
These PCB contact switches are best for situations where user feedback is beneficial. Sometimes these switches have a thin layer of plastic on the metal cap to prevent falling out.
Membrane PCB switches are among the most widely used switches in mass production because they are incredibly cheap and easy to implement.
The switch itself is nothing more than a pair of PCB contacts that sit under a piece of rubber. The rubber is coated with a carbon layer, and when the rubber is pushed over the contacts, it closes the connection.
Common uses for PCB contact switches are in remote controls, most desktop keyboards, calculators, and other mass-produced items. PCB contact switches sometimes do not have a label because they are copper features, but they are incredibly easy to spot. With carbon coating, gold-plated or tinned, but they are never just bare copper.