Rotary Switches

Rotary switches are one of the widely used types of switches that can control multiple circuits simultaneously. They move or rotate in a circle and can stop in different positions. Rotary switches offer numerous benefits compared to other types of switches, as turning the actuator around can turn different circuits on or off depending on the switch’s actuation position. These electrical devices let you select different options or settings by simply turning a knob or dial.

Rotary switches have become less common as they are sometimes replaced by electronic equipment like touchscreens. However, mechanical rotary switches still exist, especially in safety-critical equipment where a computer malfunction could lead to dangerous outcomes. 

How Do Rotary Switches Functions?

Let’s take a closer look at how rotary switches work. While they come in a variety of designs, they all share a similar basic function. At the heart of it is a spindle or rotor with a small spoke sticking out. As the spindle turns within its housing, the spoke shifts into different positions, contacting electrical terminals and either turning circuits on or off. The electrical current then travels through a round component known as a wafer, and it’s common for multiple circuits to be connected to just one position.

Popular Rotary Switch Types

Rotary switches are available in many different types, but some of the most widely used types include:

• Rotary Knob Switches: Features a rotating knob for various settings adjustments.
• Rotary Cam Switches: A built-in shaft used to increase or decrease electrical resistance in the connected contact positions.
• Dial Rotary Switches: These switches have a numbered dial that you can turn to select desired options. A classic example is an old-style rotary telephone set. 
• Momentary Rotary Switches: Applied in various electrical circuits for circuit switching, such as changing the state of function from on to off. 

Electrical Contact Configuration - Poles, Positions & Ways

Terminals are known as contact points or positions in electrical circuits. On a rotary switch, the electrical input terminal is called a pole. In some designs, there are multiple poles, each connected via rotation to a series of output terminals, which are called ways. We provide rotary switches in a wide variety of configurations, such as: 

• Double Pole, Double Throw DPDT: Two on-on switches that operate adjunctly. 
• Single Pole, Single Throw (SPST): Offers only two positions, on and off. 
• Single Pole, Double Throw (SPDT): Allows for two possible positions, often used for picking between two options.
• 2-Position Rotary Switches: A two-position switch used for on or off and momentary functions.
• 3-Position Rotary Switches: A three-way configuration switch typically used for on-off-on purposes.

What Benefits Do Rotary Switches Offer over Other Types of Switches? 

Rotary switches offer various advantages over other types of switches, such as:

• More durable and reliable.
• The rotary knob or dial provides a simple and intuitive way to select different settings.
• Compact and space-saving, especially in devices with constrained space.
• Customisable with different numbers of positions.
• Adds a classic and elegant look to electronic and electrical devices.

Application Information

• From audio/video AV equipment to household appliances.
• Machine control panels and programmable logic controllers.
• Healthcare devices and instruments.
• Modems, routers, telephones and other communications devices.