Dimmers - You thought they were simple
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- Опубликовано: 13 дек 2023
- Dimming your LED lights can be challenging. There are many practical challenges to dimming lights, from incandescent bulbs to modern LED Christmas lights to Christmas lights with built-in drivers. We test various dimming methods, including TRIAC-based and PWM (Pulse-Width Modulation) dimmers, to see how they fare with different types of bulbs including non-dimmable LEDs, dimmable LEDs, and traditional incandescent bulbs.
Discover the surprising realities of how dimmers interact with different lights, the intricacies of voltage changes, and the effects on LED bulbs. We also tackle the unique scenario of dimming LED Christmas lights with built-in LED drivers, providing insights and solutions to common dimming challenges.
Whether you're setting up your home lighting or navigating the complexities of Christmas decorations, this video is packed with practical tests, easy-to-understand explanations, and valuable tips for anyone looking to understand and master the art of lighting dimming.
Don't miss out on our hands-on tests and findings that could revolutionize your approach to home lighting. Watch now for an illuminating journey through the world of dimmers!
For Your Reference:
PWM (Pulse-Width Modulation) dimmers work by rapidly switching the LED on and off at a frequency that is typically not perceptible to the human eye. The perceived brightness is controlled by varying the ratio of the "on" time to the "off" time (duty cycle). This method does not actually change the voltage or current but controls brightness by varying the amount of time the LED is turned on.
The PWM Dimmer featured in this video: www.amazon.com/gp/product/B0B...
TRIAC dimmers operate based on the principle of phase-cut dimming, which involves altering parts of the AC power waveform to control the brightness of lights, typically incandescent bulbs. These dimmers use a TRIAC (Triode for Alternating Current) semiconductor device to chop either the leading or trailing edge of the AC waveform. The leading-edge dimming is more common with traditional resistive loads like incandescent bulbs, while trailing-edge dimming is designed for capacitive loads such as LEDs. By adjusting the portion of the waveform that is delivered to the light, the TRIAC dimmer effectively reduces the total energy supplied, resulting in dimming.
However, TRIAC dimmers were originally designed for incandescent bulbs and can encounter compatibility issues with LED lights. Since LEDs have different electrical characteristics, using a TRIAC dimmer with them can lead to problems like flickering, buzzing, or an incomplete dimming range. This mismatch arises because TRIAC dimmers are not optimized for the low power and electronic nature of LED lighting, making them less suitable for modern LED applications.
LED dimmers are specifically engineered to control the brightness of LED lights, which require a different approach compared to incandescent bulbs. The most common method used in LED dimming is Pulse-Width Modulation (PWM), where the power is rapidly switched on and off at a high frequency. The perceived brightness is controlled by adjusting the duty cycle, which is the ratio of the "on" time to the "off" time. Another method, less common in residential settings, is Constant Current Reduction (CCR), which directly regulates the current supplied to the LEDs, ensuring a constant light output.
Unlike TRIAC dimmers, LED dimmers are designed to be compatible with the electronic characteristics of LEDs, providing smooth and efficient dimming. They prevent issues like flickering or reduced lifespan, which can occur when LEDs are used with inappropriate dimming technology. LED dimmers cater to the specific needs of LED lighting, ensuring that they function at optimal efficiency and brightness levels, making them the preferred choice for modern LED lighting applications.
Hello again. Well this video could have been about 1/10 as long as it was, I listen to the whole thing while driving. The reason I clicked on it is because I was hoping you would go over pulse with modulation and the flickering that is common on LED Christmas lights. Much like you and every other human, I find tungsten lights to be orders of magnitude more appealing than any LED that has ever been made. In the Christmas light department, if the darn lights didn't flicker, it would go a long way in making them more acceptable. I was hoping you may have come across a current modulation dimmer instead of pulse width in order to battle the flickering.
Even though the topic is quite bland and not broadly attractive, the production value is top-notch as usual with your work.
You’re absolutely right about the concerns regarding LED lighting and flickering. In the realm of LED dimming, there are primarily two methods: Pulse Width Modulation (PWM) and Constant Current Reduction (CCR).
In the video, I focused on PWM because it’s the most widely available and commonly used method for LED dimming. Most PWM dimmers, like the one used in the video, operate at a frequency well over 1 kHz. This high frequency is key to why PWM dimming typically doesn’t cause perceptible flickering. The rapid cycling of the LEDs - turning on and off faster than 1,000 times per second - means that the ‘off’ time is incredibly short, shorter than the time it takes for the LED to visibly fade. As a result, our eyes can’t detect the brief intervals when the LED is off, and we perceive a continuous light.
I didn’t delve into Constant Current Reduction (CCR) in this particular episode, primarily because it’s not as commonly available for general consumer use as PWM dimming solutions. I apologize if this wasn’t made clear in the video. Your interest in CCR highlights an important area of LED lighting technology, and it’s something I might explore in future content.
The flickering you are referring to is most likely the alternating current version of the LED Christmas lights. These operate at 50hz-60hz. I also covered this in the video. I haven’t been able to see any flickering at all with the PWM dimmer I featured, even when recorded at 240fps.
Thanks for engaging with the video and sharing your thoughts. Insights like yours help shape the content for future episodes!
Thank you Sir, for this wonderful Video
Just got this recommended great production quality and content just subscribed 🙂
Me and the H&H boys are enjoying this video
WHATS COOKIN
I have two dim able lights that use a pulse with modulation to dim AC 120 volts they were used in the old torch lights that had the halogen lights. now I will have to find how they work. the 130 volts does cycle from 0 to 120 sixty times every second so do these switches just change the frequency.
I have also noticed that some bulbs seem to behave differently with leading edge vs trailing edge dimmers. Almost like some bulbs are 100% brightness at 50% trailing edge. And some LEDs flicker at low brightness with leading edge.
Can you pls make a video of for a pwm dimmer design and assembly 😅
Here's a challenge for you. Can you create a wireless 3D printed switch that you can mount to , for example, your bedroom light switch. Then use the wireless signal to turn your bedroom's light on and off.
The idea is to flip a manual switch wirelessly
120 V AC is not -120 V to 120 V, it's 120 V *RMS* and the *peak* voltage is 170 V
120 × 0.707 = ~170V for those wondering. 0.707 is sqrt(2). This is for sinusoidal signals only (which is true for AC from the grid).
@@alexanderquilty57050.7071 is the INVERSE of √2 but yeah, that's the idea.
Said differently, 120 V (omitting the sign) is the *average* voltage of the US grid.
Are you happy with your Klein DMM? I have the MM700 and do not like the display. It’s very positional. You have to look at the screen within a small cone to read the readout. I replaced the first under warranty and the second is just the same.
I don't get how the LED would need a smooth voltage increase (so no triac) but are perfectly happy with PWM (which is the sharpest of them).
Is it because of the in-rush current in capacitive dropper power supplies?
I wonder if its a stretch to say that the pwm rise time is long enough to not have the negative effect of the triac rise time for a given LED.
@@alexanderquilty5705I doubt that's the case but I'm no electronic engineer
Really excellent balance of dealing with our wonderfully complex new World problems with a practical but specific Real world focus. I think I've gone through the same processes. I believe I've heard PWM attenuation of LEDs is problematic in digital photography... I love playing with cheap electronics!
Why do you stop posting, my friend, your work is very wonderful, keep it up
Still posting plenty of shorts. Trying to decide the best long form content to create :)
@HackMakeMod There is not much high quality content like yours about electronics.. I'm starting the hobby and would love to see more videos on your channel to learn from. You make the subject fun and engaging.
So... You're making a list, will you be checking it twice? ;)
Of course! 🎅
who's still using fluorescent bulbs? Tech-averse younger boomers and older gen-x-ers. Generally they're younger than the people who only trust incandescents, but older than the people who were young enough to adjust to LEDs. I've tried explaining to so many customers that you can get LEDs now that match whatever look you want, but it's always something about eyestrain or uv light or psychosomatic headaches or just generally not liking them
(this is a generalization of course, I've run into older boomers who love LEDs and millenials who love incandescents, but when it comes to still using fluorescents it's generally people who already remember changing lighting methods once when they were already old enough to be a little stubborn about that kind of thing, and now really don't want to change for a second time)