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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 fan or a CB radio with multiple frequencies of reception or "channels". A rotary switch consists of a spindle or "rotor" that has a contact arm or "spoke" which projects from its surface like a cam.
Two light switches in one box. The switch on the right is a dimmer switch. The switch box is covered by a decorative plate. The first light switch employing "quick-break technology" was invented by John Henry Holmes in 1884 in the Shieldfield district of Newcastle upon Tyne. [1]
Two control knobs for a heating/cooling system. The left knob controls the temperature while the right controls the fan speed. A control knob is a rotary device used to provide manual input adjustments to a mechanical/electrical system when grasped and turned by a human operator, so that differing extent of knob rotation corresponds to different desired input.
Many specialized forms exist, such as the toggle switch, rotary switch, mercury switch, push-button switch, reversing switch, relay, and circuit breaker. A common use is control of lighting, where multiple switches may be wired into one circuit to allow convenient control of light fixtures.
The most common use of a pull switch is to operate a ceiling electric light.The ceiling fan and mechanical wall fans are also appliances often operated by pull switches. . Pull switches may be either two-position (open or closed) or multi-position (allowing for different fan speeds or levels of illuminati
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The rotary machine switching system, or most commonly known as the rotary system, was a type of automatic telephone exchange manufactured and used primarily in Europe from the 1910s. The system was developed and tested by AT&T's American engineering division, Western Electric , in the United States, at the same time when Western Electric was ...
In movie projection, the shutter admits light from the lamphouse to illuminate the film across to the projection screen. To avoid brightness flicker, a double-bladed rotary disc shutter admits light two times per frame of film in 24 fps projection, resulting in 24 * 2 = 48 Hz, which is the lower brightness flicker fusion threshold.