Push button switches are mechanical switches that actuate electrical circuits. When the button is pressed, the circuitry connects. When the button is released, the connection breaks. Depending on the purpose of the switch, a push button can use various actuation methods.
These simple but crucial components are prevalent in many modern applications, including electronic equipment, household appliances, magnetic locks, and more. Here is an overview of push button switches, how they work, common types, their design considerations, and typical applications.
What Is a Push Button Switch?
Push button switches control power to a device, appliance, or machine when an operator presses the button, activating the internal switching mechanism. Available in a broad range of sizes, shapes, and configurations, a push button switch can have a plastic or metal body and other specifications based on the design.
Push buttons can activate the silicon-controlled rectifier (SCR) by gate terminal, which is the most common type of push button we see in consumer electronics. There are also buttons that can provide momentary or latching action.
How Do Push Button Switches Work?
A push button switch relies on a simple in-out activation mechanism and can initiate (turn on) or break (turn off) a circuit. For a circuit to open or close, electrical contacts attached to an internal spring must connect with the points of contact found on the lower end of the switch. As the push button gets released (or pressed again, depending on the style of the switch) the spring retracts and returns the circuit to its original state.
The type of push button switch is considered either momentary—where the switch function only lasts for the time the button is pressed—or maintained, where the switch function remains latched after being activated.
Types of Push Button Switches
Push button switches can be normally open (NO) or normally closed (NC). Normally closed (ON position) switches break the circuit when activated, while normally open (OFF position) switches complete the circuit when pressed.
There are two main types of push button switches:
- Momentary: This single-pole switch is initially set to an off state. When the push button gets pressed, it changes to an on position. Double-pole momentary switches can provide additional functionality.
- Push-Pull: This switch remains in an off state until the button gets pressed, engaging the actuator. The device or machine remains in an on state until the actuator is pulled, returning it to the initial off position.
Specifications of Push Button Switches
Understanding the specifications of different push button switch types is critical to selecting the right type for your application. The voltage and current ratings are especially important to ensure compatibility with your performance criteria. Other specifications to consider when selecting the proper push button switch include:
- Termination Style: Different mounting options include PC pin, gull wing, screw terminal, wire lead, and more.
- Voltage Rating: The voltage rating specifies the maximum allowed voltage across the device, up to 24 VDC.
- Current Rating: The current rating specifies the maximum current through the device, up to 14 mA.
- Actuator Height: Available in 3.3 mm, 5.4 mm, flush, and more, actuator height is crucial when vertical space is limited or when accidental switch activation must be avoided.
- Pitch: The center-to-center distance between the pins ranges between 2.54 mm and 5.08 mm.
- Actuator Cap: Dependent on the application needs or user preference, various color options and finishes are available, with or without a cap.
- IP Rating: Push button switches are rated or non-rated to resist dust ingress and moisture.
Applications of Push Button Switches
Push button switches are used in many applications and industries. For example, marine push button switches must be able to function in harsh marine environments, with regulations specifying their manufacturing and use. Military push button switches meet designated specifications (MIL-S-8805/3 and MS25089) and can withstand specialized quality control and rigorous testing, meeting high performance and reliability requirements. These push button switches must have the following capabilities:
- Electromagnetic immunity
- Extreme temperature tolerance
- IP67 or IP68 waterproofing
- Resistance to salt spray
- Shock and vibration resistance
The experts at Amphenol NEXUS Technologies have extensive experience designing and manufacturing military and marine push button switches, as well as rugged switches used in numerous industrial and commercial settings like:
- Command systems
- Commercial and military aircraft
- Ground vehicles
- Industrial machinery
- Naval systems
- Ruggedized communications systems
- Soldier systems
Considerations When Choosing a Push Button Switch for Your Application
Push buttons can be found in diverse applications such as portable equipment, vending machines, power tools, household appliances, consumer electronics, and more. When considering which push button switch to use, consider these questions:
- How much space is available on the board?
- What is the acceptable profile height?
- Does the specific application require a maintained or momentary contact switch?
- What are the long-term effects of the operating environment on the switch function?
Reliable Push Button Switches From Amphenol NEXUS Technologies
Founded in 1961, Amphenol NEXUS Technologies produces tactile and durable push-pull and momentary switches. Our custom switches let us meet the exact specifications of your application, complying with military standards as needed.
Our 16,000-square-foot manufacturing facility in Stamford, Connecticut, employs more than 50 employees, many of whom have been with the company for more than 20 years. With a commitment to customer satisfaction, we manufacture push button switches for applications requiring a reliable, durable, and cost-effective means of switching electrical circuits.