How Does a Dimmer Switch Work?

Dimmer switches are a popular feature in many houses and are used to raise or lower the brightness of a light bulb to conserve electricity, create the right ambiance or extend the lightbulbs lifespan.

But how does a dimmer switch work? In a nutshell, a dimmer switch just decreases the voltage that your light bulb is getting by very small amounts each turn. This lets you control the brightness of the light.

However, there’s much more to it than just that. So today, we’ll be going all over dimmer switches, how they work, and more. Without further ado, let’s get straight into it.

What is A Dimmer Switch?

Dimmer switches are a type of switch that decreases the voltage waveform applied to the light. It essentially cut down parts of the voltage AC and lets only some voltage waveforms reach the light bulb, which in simpler terms, can decrease or increase the brightness to your liking.

The main power consists of an alternating flow of current at a rate of 50 to 60 cycles, also known as Hertz or Hz for short. The values 50Hz and 60Hz depend from country to country, so they might be lower or higher in your area.
So the current flows and goes up and down, changing direction at the zero point. We will cover more about this later on.

How Does a Dimmer Switch Work?

As mentioned above, dimmer switches work by changing the voltage at the zero point. You can find the zero point by simply drawing a straight line in the middle of the diagram.

If you turn your light switch off at the zero point, it’ll turn off without the light bulb flickering. In this similar way, a switch dimmer essentially does the exact same thing. Whenever you turn the switch dimmer, it lowers the frequency of the voltage right at the zero point.

But in some cases where the light bulb or the circuit is damaged, you can see that the light flickers when turning on or off or when changing the frequency.

So, in short, it just rapidly shuts on and off the light circuit, reducing the amount of current flowing through it at the zero point. This principle is used on all sorts of dimmer switches.

Along with that, switch dimmers nowadays are great at reducing the electricity cost every time you turn your light bulb too. So overall, getting LED dimmers can greatly benefit you in many ways.

What Are The Benefits Of Dimmer Switches?

As mentioned earlier, getting a switch dimmer is incredibly helpful and can benefit you in a lot of ways. So here are some of the ways getting a dimmer switch can benefit you —

Less Energy Used

Since multiple lights in your house are turned on most of the time for many hours, your electricity bill for the lights can get high even if they use a low wattage. But with a light dimmer, you can decrease the light’s brightness to your liking and decrease the amount of energy used by the light.

Even if you don’t dim them often, dimming your lights every now and then can save you a total of 18% to 20% in lighting bills. You’re helping the environment by saving energy, too.

Lights Last Longer

Along with a reduced lighting bill, dimming your lights can ensure they last much longer. Whereas a regular light bulb may last up to 1,000 hours, simply dimming your lights slightly can double or triple the amount of time it lasts. This is because it has to work less and use less voltage.

Create Comfort and Ambiance

And finally, dimming lights generally is great for comfort, especially at night. In areas like your bedroom, you’ll generally want your light to be dim enough to not hurt your eyes but also bright enough to let you see your surroundings properly. This will ensure you get better sleep too.

Or in your living room, you might want to dim the lights while watching TV or increase the lights when reading a book. Overall, there are infinite options where you can dim the lights to your liking with a switch dimmer.

What Are The Different Types Of Switch Dimmers?

There are a few types of common switch dimmers that you can find. These are listed below —

Integrated Dimmers

Some light switches, especially modern ones might have dimmers integrated into the light switch itself. So in the same place, you can turn your light on and off, and you can even decrease or increase the brightness of the light with a press of a button.

These are a great and relatively cheap option, and they look quite modern.

Touch Screen Dimmers

Touch screen light dimmers surprisingly aren’t as expensive as you might think, and they look great on your wall. Most of the time it’s just a simple, small LED screen that you can interact with to dim your lights.

A lot of the time you can find smart touch screen dimmers too, where you can control the brightness through your phone or other devices such as watches and laptops.

Slide Dimmers

As you can likely guess, slide dimmers are a type of dimmer where you slide a lever up and down to control the dimness of your lights. They’re one of the cheapest options you can find for a switch dimmer, so it’s a great option.

Rotary Dimmers

Rotary dimmers are the most common types of switch dimmers you can find. They look excellent and don’t cover much space, and you simply turn the rotary dimmer knob left to increase the brightness and right to decrease, or the other way around in some cases.

These are generally the cheapest option you can find for a switch dimmer since they’re completely manual, but it’s still an excellent option.

Multi-Location Dimmers

A lot of the time, you’ll have to buy a switch dimmer for each and every one of your light bulbs. It can end up costing as high as $50 to $100 depending on how many light bulbs you have.

For this, a multi-location dimmer can work best. It’s a single dimmer you install on your wall that decreases the light bulb’s brightness for more than one location.

Advanced multi-location dimmers can have specific dimness for specific light bulbs, but most of them dim all the light bulbs the same amount.

Frequently Asked Questions (FAQs)

Here are some of the most frequently asked questions we get —

Can a dimmer switch completely turn a light off?

If your dimmer switch is faulty, it can turn your light off completely or make it flicker. It’s rather rare nowadays, though, as most dimmers are tested before being sold.

How long do dimmer switches last?

Generally, a dimmer switch can last up to 15 years. They usually don’t break easily unless it’s hit by a huge force or a short circuit occurs between the dimmer switch and the light bulb.

What’s the difference between LED dimmers and regular dimmers?

LED dimmer switches are made specifically for dimming LED light bulbs and reduce the wattage and cost greatly. They don’t work on regular lights most of the time. All-purpose regular dimmers do work on LED lights, but not as well as regular LED dimmers.


Hopefully, now you have a good idea of the question “how does a dimmer switch work” They just turn the voltage off rapidly changing the wave flow, and with a lower voltage, you’ll get a lower brightness.

Most modern-day light dimmers can greatly decrease how much money you spend on lighting bills, so it’s a great deal to have one. Even if you don’t put it on every light bulb, a multi-purpose one can be great too.

Before purchasing one you should realize that non-LED light bulbs can’t function with a regular LED dimmer.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.