Posted by Doug Root on 8th Jun 2021

Types and Operation of Some Dimmer Light Switches

You walk into a room in a residence or a space of public gathering, and the lights are simply glaringly bright. Too bright. in fact, and something needs to be done about it. Compounding the matter further, this space - home or otherwise - is going to be used to host a gathering in short order. What can you do?

Of course, you shut off the lights, wait for them to cool, and then get on a ladder, a box of fresh bulbs in tow, and proceed to systematically replace each of them, individually. Let’s just hope you did your homework and you know the replacements will make the grade!

Reality check - that is decidedly not what you do because that makes little to no sense. What busy planner has time for that? What you do is hit the dimmer light switch on the wall, setting it to an appropriate level so that the lights provide the proper mood, lighting, and atmosphere!

That is, of course, if the location in question had a dimmer switch in the first place.

What Is a Dimmer Light Switch?

You probably don’t need a lengthy introduction to dimmer light switches, even if you lack a thorough education on electrical infrastructure or the nuances in the different forms of lighting. It’s not like a dimmer switch is a shunted tombstone socket or an electronic ballast!

No, a dimmer switch is, generally speaking, a much more familiar aspect of most lighting circuits. Though they vary in how they operate, they all more or less accomplish the same objective - to alter the ambient lighting in a room.

A dimmer switch can be easily manipulated to create a brighter atmosphere by “turning it up” or a much more subdued atmosphere, simply by “turn it down.” Many domestic settings have had dimmer switches installed that have small, adjustable dials that can give homeowners direct control over the brightness in the lighting of a space.

The most common forms of dimmers that you will encounter in a domestic setting are slide dimmers, rotary dimmers, and rocker dimmers - or some iteration of these. Slide dimmers have a sliding knob that adjusts brightness, rotary dimmers have a dial, and rocker dimmers are sort of light slide dimmers in that they have a manipulable “slide” or “rocker switch.”

With that in mind, not all dimmer light switches operate by the same principle. There are several different kinds that work in different ways, and not all of them are suitable for all forms of lighting.

How Do They Work?

Dimmers may accomplish the same perceived objective, but they do not all work in the same ways. A dimmer switch may help to dim the lights, but the manner by which it accomplishes this objective will vary. Here are some of the types of dimmers that are commonly available and in widespread use today.

●Variable Resistor Dimmer Switches

Back in the day, when most lighting was incandescent (much of it still is) most dimmer switches operated by a fairly simple principle, the principle of variable resistivity. To understand how this works you need to take a step back and evaluate the operation of an incandescent bulb.

Incandescent bulbs glow when the proper voltage and current are supplied to them. As electricity flows through the filament within the bulb, it heats up and releases some energy as light in a process known as electroluminescence. If you don’t supply the proper voltage and current, the light will not glow at its measured brightness - it will not light at all, or it will be dim.

Now, this is where a resistor comes into play. A resistor is a component of a circuit that does not conduct electricity with the same ease as the rest of the circuit. That is, it resists the flow of electrons across it. Resistors have a variety of purposes, and in this case, the purpose is to dim the lights.

In this case, the resistor causes a voltage drop before the current is fed to the light bulb, and the result is that the light bulb’s brightness drops as well. However, variable resistors have a lot of problems, and so they are not in widespread use today. For one thing, they are inefficient and you still use the same amount of electricity, which will cancel out any energy savings. They also heat up (all that energy has to go somewhere if it isn’t getting to the light) and can present a fire risk.

●Modern Dimmer Light Switches

Modern dimmer switches abandoned this old principle of variable resistivity in favor of a much safer, much more efficient, much more practical solution. This modern solution has to do with how the alternating current in our electrical systems operates.

In a system that utilizes alternating electrical current, the current itself is constantly changing direction. This change of a current’s “direction” occurs very rapidly, about 60 times per second. The way modern dimmers work is by interrupting this cycle, in effect supplying power to a light and then cutting it off, many times within a second.

Every time the current switches direction, a modern dimmer will shut off power for an instant, which occurs about 120 times per second. The effect is that the light is not supplied with full power throughout a given unit of time, which results in it appearing less bright.

This is a very, very high-level generalized view of how the process works, but there is more to the operation of these modern dimmers. This entire function is made possible by the use of a special semiconductor known as a TRIAC, or a Triode Alternating Current Switch.

The operation of a Triode Alternating Current Switch is similar to a transistor (or the diode of a light-emitting diode) in that it is made of several layers of p-type and n-type materials. The n-type material contains free electrons and the p-type material contains voids that can accommodate these free electrons.

This Triac also contains a small variable resistor, but it is not as inefficient as the variable resistors that are wired onto other circuits. In this instance, the smaller variable resistor only serves to control the voltage fed to the switch.

Basically, when you’re not dimming the lights, the Triac is open and does not interfere with the circuit. When you go to dim the lights, the resistance increases, creating a cascade of electrons that sort of slows down the current that is able to flow through the circuit. This, in turn, dims the lights.

One minor problem faced by some triac switches is that they sometimes create a buzzing or humming noise, but more modern, advanced dimmers have been made with technology that helps to counteract this.

●Magnetic Low Voltage and Electronic Low Voltage

There are also types of dimmers known as magnetic low voltage and electronic low voltage dimmers. Magnetic low voltage dimmers, which are also known as MLV dimmers, are typically used with recessed lights. Electronic low voltage dimmers are sometimes used with LEDs and are commonly used in situations where LED lights are installed.

●Electronic Fluorescent Dimming Ballasts

Some fluorescent lights, like CFLs, can be controlled or dimmed via the aid of an incandescent dimmer, whereas others may require the use of an electronic fluorescent dimming ballast. These special dimming ballasts can be used to control the perceived brightness of certain fluorescent lamps. As fluorescent lamps require a ballast to control their voltage and current anyway, special dimming ballasts only take this one step further.

●LED Dimmers

There are also some types of special dimmers for LED lights. Generally, some dimmers are used to control the power that is sent to the LED driver, adding in another layer of control over the current and voltage provided to the LED itself. In some situations, LED lights are controlled via leading edge or trailing edge dimmers. A leading edge dimmer cuts off the power to the LED along the leading edge of an AC wave, whereas a trailing edge dimmer cuts off the power along the end of an AC wave. This happens so rapidly that instead of blinking or flickering, the light appears to dim.

Why Should I Dim the Lights at All?

While your purposes might be purely aesthetic, there are actually plenty of good reasons to invest in a dimmer light switch to turn the lights down on your ceiling fan, your track lighting or just a lamp. Consider some of the following.

●Improve the mood or set accent lighting

Probably the first and most obvious reason that homeowners and business owners want to be able to dim the lighting levels is because it affects the mood of the setting. There are times when bright, harsh lighting is warranted, but there are certainly times when it is not.

For example, restaurants often have a need to dim the lights in the evening to create the perfect ambiance for a dining situation. Similarly, homeowners looking to create a similar atmosphere for evening entertainment in their own homes will seek the help of a dimmer for their lights. You can also use a dimmer to create accent lighting for specific rooms or displays.

●Extend the lifespan of your light bulbs

The use of a dimmer can be much more valuable and does not need to be solely aesthetic. Insightful implementation can also potentially have real effects on the longevity of your light bulbs.

Consider that the ballast of a fluorescent light, among other things, controls current and voltage supplied to the lamp to prevent it from overdrawing and burning out in a matter of moments. Dimmers don’t exactly accomplish the same thing, but they do cut back on power supplied to a lamp and can therefore potentially extend their lifespans.

●Potentially keep heat down

This is not as much of a concern for those that use fluorescent lights or even LED dimmer switches, but it can be a concern for those that use incandescent or halogen light bulbs, and these are common in homes.

The thing about incandescent and halogen lights is that, despite the high quality of the light output and CRI, these lights burn hot. Truth is, they burn very hot - and can drive up the temperature of a room if they are left to burn for a prolonged period of time. A dimmer, however, can limit how hot they become, potentially causing a positive impact on your cooling costs.

●You may be able to slash energy costs

Finally, there is another practical reason for the implementation of light dimmer switches, and it is expressly to incur energy savings. Because dimmer switches limit the power to a light, in some instances shutting off power for a brief moment, they will limit the power drawn by the fixture. This produces a net decrease in energy consumption, which can be pronounced for users of incandescent and halogen lights.

Is a Dimmer Switch Compatible with My Current Lighting Infrastructure?

In many instances, you can’t simply install a dimmer switch in a circuit. Not all dimmer switches or dimming technologies are compatible with all lighting systems, and you need to ensure that you are using the proper type of dimmer light switch, wattage, and even the right type of dimmer for the bulb type. Incandescent, halogen, fluorescent and even LED lights will all potentially take different types of dimmer switches, so the help of experts is in order. Whether you have questions about smart dimmer switches or lighting fixtures, Atlanta Light Bulbs is here to help!

How Atlanta Light Bulbs Can Help

For over 40 years we’ve been a partner and a valuable, strategic resource for our clients around the country. We carry not only the light bulbs and lighting equipment themselves, but we provide the knowledge our clients need to implement the necessary changes. We’re also flexible on pricing and pride ourselves on our service.

If you’re looking for a way to implement dimmer switches - in your home or business - please feel free to get in touch with us at 1-888-988-2852 and let us know what you need. We’d be more than happy to help you, whether you’re in need of information or the actual products.