Dimmer Switches

A dimmer switch is an electrical component that allows users to adjust the brightness of a light from nearly dark to fully lit, simply through the turn of aknob or slide of a lever. How do dimmer switches achieve this? This blog will look at the technology behind dimmer switches and explain how they operate.

Early dimmer switches had a relatively simple solution to adjusting light levels - a variable resistor. A resistor is a piece of material that doesn’t conduct electricity well, and offers a lot of resistance to moving electrical charge. Variable resistors feature a piece of resistive material, a stationary contact arm, and a moving contact arm. In this configuration, the resistance of the resistor can be altered by adjusting the distance the charge must travel through the resistive material. As the charge travels through the resistor, energy is lost in the form of heat. As this energy is lost, the energy available to power the lightbulb decreases, thereby dimming it.

While this configuration gets the job done, it is less efficient than modern dimmer switches, and uses a lot of energy to complete a simple task. Rather than directing energy from the light bulb into a resistor, modern resistors rapidly shut the light circuit off and on to limit the total amount of energy flowing through the circuit. This switching cycle is built around the fluctuation of alternating current (AC). AC has varying voltage polarities in the form of an undulating sine wave that fluctuates rapidly from positive to negative voltages. Modern dimmer switches chop up the sine wave, shutting off the light bulb every time the current reverses. This rapidity of the switching is based on the position of the dimmer switch's knob or slider. When turned to a brighter setting, it will switch on very quickly after cutting off. The circuit is turned on for most of the cycle, so it supplies more energy per second to the light bulb. If the dimmer is set to lower light, it will take longer to turn back on.

The main element of the switching circuit is a triode alternating current switch, also known as a triac. A triac is a small semiconductor device, much like a diode or transistor. Similar to a transistor, a triac is made up of different layers of semiconductor material. This includes N-type material, which has many free electrons, and P-type material, which has many spaces for free electrons to go. The triac has two terminals, each wired into a different end of the circuit. The two terminals always have voltage differences, but it changes with the fluctuation of the alternating current. When current moves one way, the top terminal is positively charged while the bottom terminal is negatively charged, and vice versa. The gate is also wired into the circuit via a variable resistor. This variable resistor operates similarly to the old dimmer switch design, without wasting as much energy.

At NSN Parts Now, owned and operated by ASAP Semiconductor, we can help you find all types of dimmer switch parts as well as other components for the aerospace, civil aviation, defense, electronics, and industrial markets. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, call us at 1-780-851-3631 or email us at sales@nsnpartsnow.com.


Share

April 13, 2020

Recent Twitter Posts

Semiconductor's Certifications and Memberships

Thanks for Visiting!

Before You Leave, Consider Taking a Look at Our NSN Parts Catalog. Don’t forget That We Can offer Same-Day Shipping On Most of Our Inventory!

Request for Quote

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.