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Most individual light sources can be rotated and aimed for where light is needed most in an emergency, such as toward fire exits. Modern fixtures usually have a test button of some sort which simulates a power failure and causes the unit to switch on the lights and operate from battery power, even if the main power is still on.
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]
Most LCD screens, however, are built with an internal light source. Such screens consist of several layers. The backlight is usually the first layer from the back. Light valves then vary the amount of light reaching the eye, by blocking its passage in some way. Most use a fixed polarizing filter and a switching one, to block the undesired light.
Dimmer light switch with RF-based remote control [1] A wireless light switch is a light switch that commands a light or home appliance to turn itself off or on, instead of interrupting the power line going to the light fixture. There are different ways to communicate between the switch and the fixture: [2]
A ghost light illuminating an empty stage in a darkened theatre. A ghost light is an electric light that is left energised on the stage of a theatre when the theatre is unoccupied and would otherwise be completely dark. It typically consists of an exposed incandescent bulb, CFL lamp, or LED lamp mounted in a wire cage on a portable light stand. [1]
This fir comes pre-lit with more than 250 warm-white lights adorning its more than 756 branch tips to give it a full, lush appearance. Use the included controller to alternate between eight ...
A trouble light using a compact fluorescent lamp. From top to bottom are a hook, a cage, the switch and a handle in one molding. A trouble light, also known as a rough service light, drop light, or inspection lamp, is a special lamp used to illuminate obscure places and able to handle moderate abuse.
Simple LED (Light Emitting Diode) circuit diagram. In electronics, an LED circuit or LED driver is an electrical circuit used to power a light-emitting diode (LED). The circuit must provide sufficient current to light the LED at the required brightness, but must limit the current to prevent damaging the LED.