A comprehensive guide to rocker switches
- April 13, 2023
Rocker switches are available in a variety of sizes and configurations. The most common type of rocker switch is the single pole double throw (SPDT) switch. SPDT switches have three terminals that can be used to control two circuits.
Rocker switches are also available in momentary and maintained contact types. Momentary switches are used in momentary applications such as operating a doorbell. Maintained switches are used in applications where the switch needs to remain in the ON or OFF position, such as a light switch.
Rocker switches are found in a variety of applications including marine, automotive and industrial equipment. Rocker switches are commonly used to control lights, fans, and pumps. This article will introduce the types, types, and working principles of rocker switches, and also discuss their applications and considerations when selecting them.
What is a Rocker Switch?
A rocker switch is an electrical switch that is commonly used to control the flow of electrical current in electronic devices or circuits. It’s called a “rocker” switch because it rocks back and forth to open or close a circuit, similar to the motion of a seesaw or rocking chair.
Rocker switches are usually rectangular or square with a pivot point in the middle that rocks back and forth. They are usually panel or appliance mounted and can be easily operated by pressing one end of the switch to turn on the circuit and the other to turn it off.
Rocker switches typically have two or more positions, such as on/off or multiple on/off positions, and they may also have a momentary function where the switch returns to its original position when released.
Rocker switches can come in different sizes, styles, and colors, and may have various markings or labels to indicate their function or location. They are known for their simplicity, durability, and ease of use, making them a popular choice in many electrical and electronic applications.
Types of rocker switches
There are many types of rocker switches, which can be classified according to their specific characteristics and functions.
Here are some common types of rocker switches:
Single Pole Single Throw (SPST) Rocker Switch
This type of rocker switch has a single circuit that turns on (off) or off (on) when the switch is pressed on one side and released on the other. It is the simplest form of the rocker switch and is often used for basic on/off applications.
Single Pole Double Throw (SPDT) Rocker Switch
This type of rocker switch has a single circuit with two possible output paths. It connects one circuit to either of the other two, allowing a choice between the two options. SPDT rocker switches are often used in applications that require switching between two options, such as selecting between two power sources or two different functions.
Double Pole Single Throw (DPST) Rocker Switch
This type of rocker switch has two separate circuits that simultaneously turn on (off) or off when one side of the switch is pressed and released on the other (Open). DPST rocker switches are typically used in applications that require the control of two separate circuits, such as independently controlling two devices or functions.
Double Pole Double Throw (DPDT) Rocker Switch
This type of rocker switch has two separate circuits, each with two possible output paths. It can connect each circuit to one of two other circuits, allowing a choice between the two options for each circuit. DPDT rocker switches are often used in more complex applications that require switching between multiple options or controlling multiple circuits simultaneously.
Momentary rocker switch
This type of rocker switch is designed to return to its original position when released and is often used for momentary functions, such as controlling a device or function only while the switch is pressed. Momentary rocker switches are available in various configurations, such as SPST or DPDT, depending on the application.
The structure of the rocker switches
Rocker switches come in many sizes and shapes, but they all have the same basic structure. The switch consists of a base, rocker, and contacts. The base, usually made of plastic or metal, houses the rocker and contact points. The swing arm is attached to the base and moves when the switch is pressed. When the switch is activated, the contacts complete the circuit and allow current to flow.
The Working Principles
The working principle of a rocker switch is based on its internal mechanical and electrical design. When a rocker switch is operated by pressing one end or side, it swings back and forth about a pivot point, causing the switch contacts inside to open or close, controlling the flow of electricity.
How a rocker switch works varies depending on its type, but in general, it involves the following actions:
ON Position: When one end or side of the rocker switch is depressed or toggled, the actuator moves to one side, causing the contacts to close, completing the electrical circuit and allowing current to flow through the switch.
OFF Position: When the other end or side of the rocker switch is pressed or toggled, the actuator moves to the other side, causing the contacts to open, interrupting the circuit and stopping current flow through the switch.
Momentary Function: In the case of a momentary rocker switch, the contacts are designed to close only when the actuator is depressed. Once the pressure is released, the contacts return to their original positions, interrupting the circuit and stopping the flow of electricity.
Things to Consider When Selecting a Rocker Switch
When selecting a rocker switch for a particular application, there are several important factors to consider to ensure the switch is compatible and suitable for the intended use.
Here are some key things to consider:
Electrical Rating: The electrical rating of a rocker switch refers to its maximum voltage and current capacity. Selection requires consideration of supply voltage, the current draw of the load being switched, and any potential inrush current during start-up.
Circuit Configuration: Rocker switches are available in various circuit configurations, such as SPST, SPDT, DPST, or DPDT, which determine the number of poles (circuit) and throws (position) of the switch.
Function: Consider the intended function of a rocker switch. Is it an on/off switch, a momentary switch, or a multi-position switch? Different applications may require different types of functionality.
Mounting methods: Rocker switches are available in various mounting methods such as snap-in, screw-in, or PCB mount.
Size and Shape: The size and shape of the rocker switch should fit the space available in the application. Consider the dimensions of the switch, including its length, width, and height, to ensure proper installation.
Environmental considerations: Consider the environmental conditions of the application, such as temperature, humidity, dust, and other environmental factors.
Quality and Reliability: Factors such as materials used, manufacturing quality, and reliability of the switch are considered to ensure long-term performance and safety.
Compliance and Certification: Consider any regulatory or certification requirements for your application, such as UL, CE, or RoHS compliance.
The rocker switch is a versatile and commonly used electrical switch used in a variety of applications from household appliances to industrial machinery. Understanding the types, principles of operation, and factors to consider when selecting a rocker switch is critical to ensure proper functionality, compatibility, and safety for your application.