![]() ![]() ![]() Types of dimmer Rheostat dimmer ĭimmers based on rheostats were inefficient since they would dissipate a significant portion of the power rating of the load as heat. More recent digital control protocols such as DMX512, DALI, or one of the many Ethernet-based protocols like Art-Net, ETCnet, sACN, Pathport, ShowNet or KiNET enable the control of a large number of dimmers (and other stage equipment) through a single cable. Each dimmer had its own control wires, resulting in many wires leaving the lighting control location. The wire for the control systems was much smaller (with low current and lower danger) than the heavy power cables of previous lighting systems. When solid-state dimmers came into use, analog remote control systems (such as 0-10 V lighting control systems) became feasible. To house this device, he decided on a 2-inch round device with one end capable of being screwed into a light bulb socket and the other end able to receive a light bulb. In 1966, Eugene Alessio patented a light bulb socket adapter for adjusting a light level on a single light bulb using a triac. This small device allowed the dimmer to be installed in a standard electrical wall box while saving energy. Spira, who would found the Lutron Electronics Company in 1961, invented a dimmer based on a then-new solid state switching device called a Silicon Controlled Rectifier or SCR. In 1896, Granville Woods patented his "Safety Dimmer", which greatly reduced wasted energy by reducing the amount of energy generated to match desired demand rather than burning off unwanted energy. ![]() This required all power to come through the lighting control location, which could be inconvenient, inefficient and potentially dangerous for large or high-powered systems, such as those used for stage lighting. History Įarly dimmers were directly controlled through the manual manipulation of large dimmer panels. The device is small enough to fit into a regular wall box provided for a switch. Their cost is about the same as the older "dimmability" circuitry that they replace in LED bulbs, fixtures or drivers.Ī residential-type dimmer switch with sliding knob to change brightness. They enable computer control via networked switches, but do not require it. A simple communications protocol, such as Blink'n'Dim, delivers dimming commands via the power line. Most recently, software programmable internal dimmers can use signals from the same switch that turns lights on and off to control dimming. Since semiconductor or solid-state dimmers switch quickly between a low resistance "on" state and a high resistance "off" state, they dissipate very little power compared with the controlled load. A variable resistor would dissipate power as heat and acts as a voltage divider. Modern dimmers are built from semiconductors instead of variable resistors, because they have higher efficiency. Dimmers with direct manual control had a limit on the speed they could be varied at but this problem has been largely eliminated with modern digital units (although very fast changes in brightness may still be avoided for other reasons like lamp life). In the professional lighting industry, changes in intensity are called "fades" and can be "fade up" or "fade down". ![]() In newer systems, these protocols are often used in conjunction with Ethernet. Modern professional dimmers are generally controlled by a digital control system like DMX or DALI. Small domestic dimmers are generally directly controlled, although remote control systems (such as X10) are available. More specialized equipment is needed to dim fluorescent, mercury-vapor, solid-state, and other arc lighting.ĭimmers range in size from small units the size of domestic light switches to high-power units used in large theatrical or architectural lighting installations. Although variable-voltage devices are used for various purposes, the term dimmer is generally reserved for those intended to control light output from resistive incandescent, halogen, and (more recently) compact fluorescent lamps (CFLs) and light-emitting diodes ( LEDs). By changing the voltage waveform applied to the lamp, it is possible to lower the intensity of the light output.
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