How Does A Dimmer Switch Work (With Diagram)?

Skip to content What is a dimmer switch and how does it work? Have you ever wondered how does a dimmer switch work? Modern-day homes typically have this switch connected to their light fixtures. The dimmer switch allows you to control the brightness of the lights to change the room's ambiance.

Home » Smart Light Switches » What is a dimmer switch and how does it work?

• Article by: Adrian Dance
• Technical & real world expert in all things IoT & smart home automation
• Updated on: June 3, 2022

Table of Contents

Have you ever wondered how does a dimmer switch work? Modern-day homes typically have this switch connected to their light fixtures. The dimmer switch allows you to control the brightness of the lights to change the room’s ambiance. An additional benefit is saving on your power bills by using only the amount you actually need.

You’ll also prolong the life of your fixtures. Installing a dimmer switch is easily done and is a simple step-by-procedure. But, if you want to know how does a light dimmer work, we have the answers for you. Read ahead for some detailed and interesting info.

What does a dimmer switch do, and how does it work?

To explain simply, a dimmer switch raises or lowers the brightness of the electric lights in your home or workplace. These devices not only help to reduce your electricity bills, but also enhance your security systems. Contemporary dimmers are compatible with smartphone apps so that you can control the luminance of the lights from a remote location. 

To understand how does a dimmer switch work, you must first understand how your power systems work. The main power your home receives is an alternating current that flows in one direction and then the other.

The current follows two alternative pathways in quick succession along with the power cables at speeds of 50 to 60 cycles per second. These cycles called Hertz work at specific speeds depending on the power systems used by the country. If you examine the current or waveform, it appears in the shape of a stretched “S” lying horizontally. 

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The specific point when the power S waveform changes direction is the “Zero” point or crossing point. This is the exact point when the current stops for a split second. Your dimmer switch acts on the power current at this point to turn it off and on.

The entire mechanism works smoothly and so fast that you’ll never notice any flickering. Each time the power cycle or sine wave crosses the zero point or half phase, the dimmer switches the light off and on rapidly.

The entire process works around 100 to 120 times per second. Essentially, the dimmer chops up the waveform into sections, just as you see in the diagram below. The interval between the on and off functions determines the room’s brightness. And, that explains how do dimmers work.

Does a dimmer switch reduce voltage or current?

When trying to understand How a Dimmer Switch Works, know that they don’t reduce the voltage or current. Say, for example, you configure the dimmer switch to the highest luminance. It will turn on the current going to the light almost instantly after zero point.

Since the circuit is relaying power for a longer interval, the light fixture receives more energy per second. This is why it seems brighter. 

However, if you set the dimmer switch to a lower brilliance, it will delay the current passing through the circuit. The light fixture receives less energy per second and thus appears dimmer.

Since contemporary dimmer switches are 99% efficient, they waste less than 1 watt of energy when controlling a light bulb of 100 Watts. And, that’s why dimmer switches help you conserve power. 

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Can you put a dimmer switch on any light?

You can install a dimmer switch on any light fixture in your home or commercial space. As long as the light uses the standard on/Off function, installing a dimmer switch should not be a problem. Also, the light should be dimmable to work with the dimmer switch. There are, however, a few other criteria to consider, and taking the time to learn how does led dimmer work helps. 

Do you intend to integrate the dimmer switch with your smart home automation systems? 

If you intend to connect the dimmer switch with the Wi-Fi, you’ll need a smart dimmer. Invest in a model and brand that you can control with a portable device, like a smartphone or tablet. Philips Hue and Leviton are good brands that come with mobile apps to integrate a Wi-Fi-enabled dimmer. Then again, the Philips Hue also works with a remote included in the package. 

Several dimmers now work with smart home hubs like Google Home and Amazon Echo. So, you’ll purchase models that are compatible with the particular home automation systems you have.

Running dimmer switches with Bluetooth connectivity is also an option. Bluetooth devices, however, have a limited range which takes away from their flexibility. You might want to choose them carefully, 

What are the light bulbs and fixtures you’re using?

Knowing How a Dimmer Switch Works can come in handy when you’re working out compatible light fixtures. That’s because smart light fixtures work well with smart dimmer switches. Before buying a new device, you might want to check the existing types and models you have. That is unless you intend to give your entire home a makeover with entirely new systems. 

With that being said, you can install standard dimmer switches with halogen bulbs and incandescent bulbs. These options are great for users looking for economical lighting solutions. That’s because they enable dimming the brightness from 0% to 100%.

While you can also get dimmers for LED bulbs and fluorescent bulbs, you can expect to control up to 20% of the brightness. When purchasing your LED bulbs, look for advanced models that work with dimmers. 

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What are the different types of dimmers?

Now that you have a fair overview of how does a dimmer switch work, let’s examine the different types now available. 

Standard dimmer switches

Standard dimmer switches are of different kinds:

• Single-pole dimmers work to control a single or multiple light fixtures from a single switch or location. You can use them to replace the conventional On/Off switch. You can buy the best single-pole smart dimmer switch on Amazon.
• Multi-way dimmers are suitable for light fixtures that have multiple control points either within or outside the room.
• Plug-in dimmers are ideal for plug-in light fixtures like, for example, table lamps. You’ll plug the dimmer into the wall power outlet and then plug the lamp into the dimmer. Adjusting the dimmer lets you control the brightness of the lamp.
• Slider dimmers allow you to slide the switch or button up and down or back and forth to control brightness. 
• Rotary dimmers are again manual dimmers that you can rotate to control the room’s brightness. Typically, the button can be pressed to switch the lights on and off. 

Smart dimmers

Aside from these standard dimmers, modern technology now offers smart dimmers compatible with wireless technology. You can install them in any of the options above. 

• Integrated dimmer switches work through your smartphone or any other mobile device. You can control the lights remotely, but the devices also have a manual function for operating. These dimmers are suitable for smart home automation systems and security networks. You can buy the best smart dimmer switch on Amazon.
• Touch-screen dimmer switches come with a display panel that allows you to change the settings by manipulating controls on the screen. 

How do I test a dimmer switch?

Now that you understand how does a light dimmer switch work, let’s talk about how to test the device after installation. Use the alligator clips on your continuity tester by attaching one to each of the dimmer wire leads.

If the LED light inside the device lights up, it’s an indication that the dimmer is working fine. Other indications are that the light fixture does not respond to the controls, or you notice flickering. If you hear a buzzing sound or the dimmer switch seems hot to touch, you’ll know that it needs to be replaced.

Here’s another tip, if you have a digital display panel, look for an error code: “OL” if the device is in the “OFF” position.  

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How do I know what kind of dimmer I have?

The best way to identify the kind of dimmer you have is to confirm the number of light fixtures it controls. You’ll also check if you can turn the light fixture off and on from multiple locations. If you can, only one of the switches can be a dimmer for controlling the brightness.

The others will have to be standard On/Off switches. Checking the wiring in the device is also a good indicator. You will have three wires running from the light fixture to the dimmer. And, four wires running from the dimmer to the On/Off switch in a standard 3-way dimmer switch wiring. That should answer your questions about how does a light dimmer work.

In Conclusion

Reading up this article should give a fair overview of how does a dimmer switch work. Install one of these devices in your home or commercial space and be impressed at how efficiently the ambiance changes. 

About Our Smart Home Automation Author

Snow Dance

You might call me a techie or a technology enthusiast. I’m one of those people whose largely self-taught in the worlds of computing, technology and engineering. I have a DIY approach to the use of software and hardware, and think that with the right advice, anyone can improve their lives through greater use of smart home technology.

Read more about Snow PrevPreviousNest Note N260 Error Code: What is it and How to fix It? Nextiotty Smart Switch Review – Elegant Light Switch with Integrated Wi-FiNext

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