Dimmer - Wikipedia. Dimmers are devices used to lower the brightness of a light. By changing the voltage waveform applied to the lamp, it is possible to lower the intensity of the light output.

Although variable- voltage devices are used for various purposes, the term dimmer is generally reserved for those intended to control light output from resistiveincandescent, halogen, and (more recently) compact fluorescent lights (CFLs) and light- emitting diodes (LEDs). More specialized equipment is needed to dim fluorescent, mercury vapor, solid state and other arc lighting. Dimmers range in size from small units the size of a light switch used for domestic lighting to high power units used in large theatre or architectural lighting installations. Small domestic dimmers are generally directly controlled, although remote control systems (such as X1.

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Modern professional dimmers are generally controlled by a digital control system like DMX or DALI. In newer systems, these protocols are often used in conjunction with ethernet. In the professional lighting industry, changes in intensity are called . Dimmers with direct manual control had a limit on the speed they could be varied at but this issue has been largely eliminated with modern digital units (although very fast changes in brightness may still be avoided for other reasons like lamp life). Modern dimmers are built from semiconductors instead of variable resistors, because they have higher efficiency. A variable resistor would dissipate power as heat and acts as a voltage divider. Reviews Microsoft Security Essentials 2011 Ram. Since semiconductor or solid- state dimmers switch quickly between a low resistance .

I have a porch light controlled by a wall switch in my entryway. Rather than having to manually turn this light on at night and off in the morning (or wors. How to Fit a Dimmer Switch; advice on fitting and wiring a dimmer light switches. Information on regulations and installation of dimmer switches for UK homes. First, twist the wires together, and then screw on the wire nut. Push the new switch back into the electrical box and screw it in place. The body of a dimmer is.

The device is small enough to fit into a regular wall box provided for a switch. History. 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.

In 1. 89. 6, Granville Woods patented his . Spira, who would found the Lutron Electronics Company in 1. 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. The wire for the control systems was much smaller (with low current and lower danger) than the heavy power cables of previous lighting systems.

Each dimmer had its own control wires, resulting in many wires leaving the lighting control location. More recent digital control protocols such as DMX5. DALI, or one of the many Ethernet- based protocols like Art- Net, ETCnet, s. ACN, Pathport, Show. Net or Ki. NET. They were large and required plenty of cooling air. Because their dimming effect depended a great deal on the total load applied to each rheostat, the load needed to be matched fairly carefully to the power rating of the rheostat.

Finally, as they relied on mechanical control they were slow and it was difficult to change many channels at a time. Saltwater dimmer. The closer the contacts to each other, the more voltage was available for the light. Salt water dimmers required regular addition of water and maintenance due to corrosion; exposed parts were energized during operation, presenting a shock hazard. Rotated 9. 0 degrees apart, the secondary coil is affected by two equal but opposite fields from the primary, which effectively cancel each other out and produce no voltage in the secondary.

These coils resembled the standard rotor and stator as used in an electric motor, except that the rotor was held against rotation using brakes and was moved to specific positions using high- torque gearing. Because the rotor did not ever turn a complete revolution, a commutator was not required and long flexible cables could be used on the rotor instead. Autotransformer dimmer. While they were still nearly as large as rheostat dimmers, they were relatively efficient devices.

Their voltage output, and so their dimming effect, was largely independent of the load applied so it was far easier to design the lighting that would be attached to each autotransformer channel. Remote control of the dimmers was still impractical, although some dimmers were equipped with motor drives that could slowly and steadily reduce or increase the brightness of the attached lamps. Autotransformers have fallen out of use for lighting but are used for other applications. Solid- state dimmer. Semiconductor dimmers switch on at an adjustable time (phase angle) after the start of each alternating current half- cycle, thereby altering the voltage waveform applied to lamps and so changing its RMS effective value. Because they switch instead of absorbing part of the voltage supplied, there is very little wasted power. Dimming can be almost instantaneous and is easily controlled by remote electronics.

This development also made it possible to make dimmers small enough to be used in place (within the pattress) of normal domestic light switches. The switches generate some heat during switching and can also cause radio- frequency interference. When the dimmer is at 5. V in Europe) and the sudden surge of power causes the coils on the inductor to move, creating a buzzing sound associated with some types of dimmer; this same effect can be heard in the filaments of the incandescent lamps as . The suppression circuitry may be insufficient to prevent buzzing to be heard on sensitive audio and radio equipment that share the mains supply with the lighting loads.

In this case, special considerations must be made to prevent this interference. This unit is wired in series with the load. Diodes (D2, D3, D4 and D5) form a bridge which generates pulsed DC. R1 and C1 form a circuit with a time constant. As the voltage increases from zero (at the start of every halfwave) C1 will charge up.

When C1 is able to make Zener diode D6 conduct and inject current into the SCR, the SCR will fire. When the SCR conducts then D1 will discharge C1 via the SCR. The SCR will shut off when the current falls to zero when the supply voltage drops at the end of the half cycle, ready for the circuit to start work on the next half cycle. This is an example of a Leading Edge Dimmer. The red trace shows the output device switching on about 5.

Switching the thyristor on earlier in each half cycle gives a higher output voltage and brighter lights. Dimmers based on Insulated- gate bipolar transistors (IGBTs) do away with most of the noise present in TRIACs by chopping off the falling side of the sine wave. These are termed Trailing Edge Dimmers.

An even newer, but still expensive technology is sine- wave dimming, which is implemented as high power switched- mode power supplies followed by a filter. The black box at the upper left is a demultiplexer.

Analogue dimmers usually require a separate wire for each channel of dimming carrying a voltage between 0 and 1. V. Some analogue circuitry then derives a control signal from this and the mains supply for the switches.

As more channels are added to the system more wires are needed between the lighting controller and the dimmers. In the late 7. 0s serial analogue protocols were developed. These multiplexed a series of analogue levels onto a single wire, with embedded clocking signal similar to a composite video signal (in the case of Strand Lighting's European D5. US standard AMX1. Digital protocols, such as DMX5. Ultimate Guitar Tabs Chords Android Sdk. In early implementations a digital signal was sent from the controller to a demultiplexer, which sat next to the dimmers. This converted the digital signal into a collection of 0 to +1.

V or 0 to - 1. 0 V signals which could be connected to the individual analogue control circuits. Modern dimmer designs use microprocessors to convert the digital signal directly into a control signal for the switches. This has many advantages, giving closer control over the dimming, and giving the opportunity for diagnostic feedback to be sent digitally back to the lighting controller.

How to Install a 3 Way Switch. Make life easier with a three- way switch. Tired of having to walk up a flight of stairs or across the room to turn on a light? The solution is to add a second switch in a convenient location. No more extra trips across the room or fumbling up a dark stairway. Controlling a light from two switches is a bit more complicated than first meets the eye, especially if you’re dealing with finished walls. The key ingredient is a special type of switch called a “three- way” switch.

You’ll need two of them, one to replace the existing switch and another for the new switch location. With these, you’ll have the convenience of turning a light on and off from two spots. In this article, we’ll show you how to run a new electrical cable and connect the two switches. We’ll also tell you how to resolve the most common complication—replacing an undersized electrical box so your work is safe and conforms to the electrical code. While this project isn’t difficult, it does require basic electrical skills: running cable correctly and making solid wiring connections. If you don’t have wiring experience or if you get in over your head, don’t hesitate to call in a licensed electrician. Apply for an electrical permit at your local inspections department before starting so an electrical inspector can check your work.

If your wall framing is open (an unfinished basement or garage, for example), you can easily run the new cable and complete this job in only two hours. However, if the cable has to run through closed walls allow several more hours. In addition to standard tools, you may need a “fish tape” to pull wire in closed walls. Also, if you don’t have a voltage detector, buy one so you can check for live wires and avoid hazardous shocks. You can find them at a home center or hardware store. Plan the wire path.

To start, decide where you want the second switch. You’ll run cable from the existing switch to this new switch location, so look for the most accessible path between the two (Figure A). If possible, start at one switch location, run the cable straight up through the stud cavity in the wall to the attic, then come back down through the wall to the second switch. Or feed the cable down into the basement or crawl space, then come back up.

If neither option works for your situation, you may have to run cable horizontally through the walls or through the ceiling. This takes extra effort because you have to cut into, and later repair, finished surfaces. Avoid exterior walls, where you’ll run into obstacles such as windows, doors and insulation. If you can’t find an unobstructed path for the cable, move the new switch location.

Once you decide on a path, measure the amount of cable you need, then add 1. It’s better to waste a couple of feet than to come up short! You’ll also need a wire stripper, 1. Figure A: Typical Cable Paths. To add a second switch, find the easiest way to run a new cable from the existing switch to the best second switch position. Cable path from the ceiling to the wall. Prep the switch locations.

Photo 1: Remove the existing switch. Remove the cover plate to the existing switch (the power is off). Then unscrew and remove the switch. Cut the electrical box loose and remove it. Photo 2: Fish cable to the new switch box.

Cut a hole for the second switch box. Drill holes as needed in the framing and fish a new cable through the wall back to the old switch position. Shut off power to the existing switch, unscrew it from the electrical box and pull the switch out of the box.

Avoid touching the screw terminals until you confirm that the power is off with your voltage detector. If the detector lights up, then the power is still on.

Find the circuit breaker (or fuse) that shuts it off. Unhook the wires to the switch (Photo 1). In most cases, the existing electrical box will be too small to contain the additional wires and connectors needed for the three- way switch (see “Sizing the Box,” below, to find out). You’ll have to replace the old box with a “remodeling box” anyway so you can pull in the new cable (Photo 3). A remodeling box has clamps that secure the cable to the box.

You can mount it solidly in drywall without cutting open the wall. Label and unhook any wire connections that are inside the existing box (wires that weren’t connected to the switch). Then unscrew the grounding screw and cable clamps (if any) in the box. Slip a hacksaw blade between the old box and the wall stud and cut the nails. Simply use the new box as a pattern, trace around it on the wall, and enlarge it with a drywall saw. Don’t cut the hole too large; you want a tight fit. Next, fine- tune the position for the second switch.

Use a stud finder to find potential obstacles, such as framing. If possible, keep the second switch the same height off the floor as the first switch. Trace an outline of the box on the wall, then cut the opening with a drywall saw.

Don’t mount the new boxes until you run the new cable. CAUTION! Turn off power at the main circuit breaker panel before unhooking the existing switch, then check the wires with a voltage detector to verify that the power is off. Key Wiring Components: 3- Way Switches and 1. Cable. Three- way switches are always installed in pairs to control a light from two locations. The switches have three hot screw terminals—one “common” and two “travelers”—and a grounding terminal. The position of the screws varies by manufacturer, but the common terminal is always a different color than the other two hot terminals. Unlike other switches, you won’t see “On” and “Off” markings on the toggle, since either switch can control the light.

You’ll find 1. 4- 3 cable at any home center or hardware store. If the circuit breaker is 2. You’ll need 1. 4- 3 or 1. A 3- way switch has three hot screw terminals. Run 1. 4- 3 cable between the switches.

Photo 3: Pull the cables through the box. Insert the cables into a remodeling box from the backside at each box location. Pull the cables from the front as you push the boxes back into the wall.

We won’t go into the details of running the cable, because each situation is different. But if the walls are open, your job is easy.

Drill a 3/4- in. If you’re going up through an attic or down through an open basement, drill through the center of the wall plates (top and bottom framing members). If you can’t go up or down, you may have to run the cable horizontally through finished walls. If so, cut a 3- 1/4- in.

Cover the notch and cable with special nail guards and patch the drywall holes. Strip 1. 2 in. Insert the cable into the electrical boxes from the backside (Photo 3). It’s easier to push cable through the back than to pull it from the front. The first switch location has an existing 1.

Wrap the cable with electrical tape where the sheathing ends to help it slide into the box. Pull the cables from the front as you slide the box into the wall opening. Pull the cable at an angle that minimizes pressure on the plastic cable clamp in the box.

Otherwise, the sheathing could snag or the clamp could break. The cable sheathing should extend 1/4 in. Tighten the screws at the top and bottom of the box to clamp it into place.

Figure B: 3- Way Switch Wiring. The key to wiring two three- way switches is to run the two wires that were originally connected to the old switch (Photo 1) to the “common” terminals. The “travelers” can go to either terminal. How to wire a 3- way switch. Wire the switches. Photo 4: Attach the wires to the switch. Clamp the first electrical box to the wall.

Connect a three- way switch, the ground wires and all other wires following Figure B. Photo 5: Tape the hot white wire.

Wrap the second white wire with black tape to show that it acts as a hot wire. Fold the wires back into the box and screw the switch into place.

Photo 6: Attach the second switch. Clamp the second electrical box to the wall and wire a three- way switch, following Figure B. Snap off the plaster ears and install the switch.