Switches are a fundamental part of electrical systems, allowing us to control the flow of electricity to various devices and appliances. One type of switch commonly used in many applications is the push button switch. These switches are designed to be pressed or pushed to make or break a circuit.
They are commonly used in control panels, machinery and other industrial environments. In this article, we will explore the different types of push-button switches and their applications to give you a comprehensive understanding of this important component in your electrical system.
What is a Push Button Switch?
A push-button switch is recognized as a mechanical apparatus utilized within a control circuit. The device necessitates manual intervention from an operator for activation, whereby the operator depresses the button to instigate an internal switching mechanism.
These push-button switches are engineered with easily distinguishable designs, often crafted from robust materials such as metal or plastic to tolerate the rigors of frequent usage.
The design of these buttons may either be flat or custom-moulded according to ergonomic standards, providing effortless operation whenever required. To summarize succinctly, a push-button switch serves the functional purpose of controlling and managing the operational state of an array of appliances or circuits.
How Does a Push Button Switch Work?
When you press the button or actuator, it applies pressure to the internal spring. The depression of the spring then makes the switch fixed to its stake position, located at the bottom of the button. This pressure, in turn, closes or opens the electric circuit connected to the switch. When you again repeat the action, the spring retracts, and the switch reaches another stable position.
Most push-button switches function in the same way. Pressure is placed on the button or actuator, resulting in the depression of the internal spring and contacts and the touching of stable contacts at the bottom of the switch. This process will either close or open the electrical circuit. You can choose between push buttons featuring normally open or closed contacts, which change state upon actuation.
Where are Push Button Switches Used?
Button-activated switches have a broad spectrum of applications, encompassing areas such as industrial machines, domestic appliances, computer systems, control interfaces, automated doors and security setups.
They also find use in audio equipment, lighting infrastructure, access regulation mechanisms, elevator controls and public address systems. These switches are adept at rendering functionalities that range from device activation or deactivation to initiating distinct action types.
Buttons often employ specific coloring schemes to denote their respective functions, effectively minimizing the potential for inadvertent activations. Typically, a red button signifies a ‘stop’ command while green frequently represents a commencement or ‘start’ operation.
Emergency stop buttons are distinguished by their high-contrast red coloration set against a yellow background for optimal visibility. Moreover, these buttons typically feature enlarged heads to streamline accessibility and ensure user-friendly operation.
Push Button Switch Types
Based On Shape
- Square
Square switches have a square shape or rectangular-shaped buttons. Usually, single-pole, single-throw switches are found in this variant. But most modern push switches come with rectangular or square buttons.
- Round
Typically, round push switch buttons exhibit a spherical or circular formation.
- Triangles or other shapes
Due to a special need, the button will be customized to an irregular shape.
Based on Performance / Function
- Single Pole, Single Throw
The single pole single throw switch or SPST switch is a push button switch used to disconnect or reconnect a single conductor in a single branch circuit. Such switches usually come with two terminals. It is mainly used to manage the power supply of an electronic circuit. Besides that, it is also used as a regular on-off witch. Such switches usually remain in their “off” position, and when pressed, they get to the on position. When released, the SPST switch returns to its off position.
- Single Pole Double Throw
Single pole double throw or SPDT switches connect or disconnect the single conductor with one of the two present single conductions. Such switches have three terminals and can be used as a “three-way switch.” That means SPDT switches can be in on or off positions and can be used to turn on two devices with different push actions.
- Normally Open
The Push to make or “Normally Open” or ON switch is a switch that activates an electric circuit. When you first press the button, the spring causes the circuit to open and the electricity flows through it. Then again, when you repress the button, the spring returns to its original position, and the electronic circuit is broken. Doorbell switches, calculators, or keyboards are Normally Open switches.
- Normally Close
The other switch is the “Normally Close” or NC switch. When you push the NC switch, the present is pressed, which breaks the electric circuit. When it is pushed back, the circuit is opened again.
- Double Pole, Single Throw
The double pole single throw or SPST switches come with four terminals. It is a type of push switch that connects two different circuit conductors in a single circuit but not with each other. Here the term Pole indicates the number of circuits that the switch can control, and the “Throw” indicates the extreme position of the actuator. Usually, the switches work together and can be used with the “ON/OFF” configuration, i.e., two terminals for the “ON” position and the other two for the “OFF” position.
- Double Pole, Double Throw
Double pole double throw switches or DPDT switches connect two conductors with two different circuits. Such switches come with six terminals, including two independent input and four output terminals. The output terminals are separate. At present, DPDT switches are the most advanced designs.
- Momentary
Momentary switches are the switches that need constant pressing to work. Such a switch will remain in one position if you apply pressure on them. The switches instantly return to their original positions when the pressure is released. For example, the buzzer bell, the hand or foot control switches of hospital beds, etc.
- Latching
Latching switches are specialized types of mechanisms that maintain a consistent position even under pressure. They have the capability to establish or sever electrical circuits for sustained functionality. These latching switches are predominantly found within residential settings, serving as the standard electrical components commonly utilized to activate or deactivate power supplies.
Conclusion
The push button switch is a multi-functional switch widely used in various industries. They provide a simple and reliable method of controlling a circuit or device. They play an integral role in daily operations and complex machinery.
This article provides an overview of the different types of switches and their use in different settings. Understanding the features and benefits of these switches can help professionals make informed decisions when choosing the right switch for their specific needs.