Rotary switch
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A rotary switch is a switch operated by rotation. These are often chosen when more than 2 positions are needed, such as a three-speed
A rotary switch consists of a
Rotary switches were used as channel selectors on television receivers until the early 1970s, as range selectors on electrical metering equipment, as band selectors on multi-band radios, etc.
Modern rotary switches use a "star wheel" mechanism to provide the switching positions, such as at every 30, 45, 60, or 90 degrees. Nylon cams are then mounted behind this mechanism and spring-loaded electrical contacts slide around these cams. The cams are notched or cut where the contact should close to complete an electrical circuit.
Some rotary switches are user-configurable in relation to the number of positions. A special toothed washer that sits below the holding nut can be positioned so that the tooth is inserted into one of a number of slots in a way that limits the number of positions available for selection. For example, if only four positions are required on a twelve position switch, the washer can be positioned so that only four switching positions can be selected when in use.
Gallery
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Bottom view of a 12-position rotary switch showing wiper and contacts.
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Rotary switch circuit
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Rotary switch handle as seen from below
References
- "A Complete Guide to Rotary Switches". RS. 3 February 2023. Archived from the original on 21 March 2023.
See also
- Commutator (electric) – Device for changing direction of current
- Control knob – Rotary device used to operate mechanical or electrical device system
- Rotary encoder – Electromechanical device
- Rotary system – Electromechanical telephone switch
- Stepping switch – Electromechanical multi-pole switch controlled by a chain of pulses