How does a dimmer work?
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- Опубликовано: 28 июн 2016
- Does a light dimmer just reduce the voltage to the lamp? Watch the video and find out what the output of a dimmer really is.
for more information and explanation as well as component parts see www.digikey.com/en/articles/te...
I learned one thing when I was 14 years old, my sister knew I liked electrical things so she bought be a dimmer switch for my birthday. I had it wired in a electrical box with the end of an old orange extension cord as the outlet. I used it on a table lamp in my room. until I wondered what would happen if I plugged my mom's washing machine into the outlet. I set the machine on agitate, and slowly tuned the dimmer down. the motor did slow down and there was pop noise and the machine suddenly went on full tilt and the dimmer was totally bypassed. when I took it apart, I found out I had literally blown the triac in two.
lessons learned by a teen who had and undying curiosity and too much time on his hands
that's a nice story
That’s interesting, cool story!
I didn’t do electricity yet but in 1978 I was 14 and took my bike apart. I left with my friends before putting it back together.
When I came home my bike was gone. It had been given away to the yard man because I “broke” it. My stepfather said “If it ain’t broke, don’t fix it”.
My current water heater is original to my home… inspection date says 1978…. Still works….
I asked myself this question today while looking at a lamp with an inline dimmer, and knew that its impossible for something small enough to fit in your hand to be an effective variac. Thanks for your explanation!
Good video. When I was a teen, just getting into electrical and electronics, I always believed it was a just variable resistor. As I got older and smarter, I realized that I was wrong. In fact very old dimmer switches actually were variable resistors, they wasted a ton of energy as heat and got quite warm, even with smaller lamps. In theater and stage lighting years ago in addition to variable resistor, they used variable autotransformer (variac) or older yet, salt water dimmers, also known as piss pots, for the ammonia like stench as the salt water boiled away. It's been rumored, that some lighting technicians would litteraly urinate in the containers to replenish the salt water , I'd imagine doing so would be painful so say the least, if the current was still on or something turned it on. 😲
WOW! haha :)
That is a great demo. I never knew how it worked. Your demo is crystal clear.
Thank you for spending the effort and time to make this. This what the internet was made for and hope it lasts many years for people looking for knowledge.
3:26
Nice video and explanation! The only thing is the volume is way too quiet during the demonstration. I'm planning on showing this during my next electrical apprenticeship class. I just have to watch that volume at the END!
Thanks. It is an old video and at the time I did not have the knowledge to fix it. I can't edit the current video other than to shorten it up in the youtube editor, which I did.
When electricians that say a dimmer reduces the amount of voltage the bulbs receive, they are Exactly Right! To be precise, they should say the 'RMS voltage' which is for layman the working voltage fed to a resistive load. Any quality voltmeter that can read AC True RMS Voltage will measure the voltage reduction as you vary the Dimmer. Just because the dimmer voltage waveform is strange looking to a novice, doesn't change the fact that this strange waveform shape does not represent a reduction in supplied voltage to the bulbs. Look into any Engineering Calculus II book under Integrals and then look up 'RMS'. Experienced engineers can look at this familiar TRIAC / DIAC circuit voltage waveform and give you a good approximation of the reduced bulb RMS voltage provided by the dimmer.
Good read, thought it was a the duration that was reduced.
amazing explanation, was really wondering what a dimmer did to a sinus (voltage) wave and what phase cut really meant. please recapture the audio and leave the music out. your video will have a lot of hits then, im sure.
Great demonstration. Just want to say that putting a massive beat at the end of the video with poor audio made for quite the surprise since I had my speakers all the way up. Not sure if you realized this when uploading the video!
Thank you for the explanation :)
Seems like the sound was dimmed as well...
Can u use an ac dimmer to current limit a dc motor
This was educational af. Thank you
Stellar video! Cheers
Great video, just one observation. The deadbands between the positive and negative half-cycles of the output sine wave are a design margin for safety and not the consumption of energy by the dimmer switch. If the positive and negative portions of the sine wave were continuous (no deadband), that would short-circuit the voltage input to the switch, which would cause a fire and/or damage the switch. These dimmers do not consume much energy at all, just parasitic losses associated with non-ideal tyristors.
Thank you for that additional insight!
Your not only reducing voltage but light speed, or photon speed because it is less it cannot be seen as far away or "d" distance; and it is a variable of light speed, just like a fires heat, the further away the less heat you feel and less photons reach your eyes, not as bright = displacement, so it is variable or this switch would not work at all in the demonstration.
E=mv^2 or E=mv^3 so, decay rate is variable because if you were next to the Sun the gamma-rays would decay you away fast. Not just the heat.
Great demonstration!
Ok its not the Voltage but what about the current?And are we able to use a dimmer as a motor controller.
Does frequency affects triacs...?
Now try to adjust volume on the actual movie ;) My amp revved up to hear you speak and then annoy the neighbours with your outro..
But thanks for the upload, not completely clear, because what is wider? Is that the frequency that changes? What about current? Does that change? Thank you.
DAMNIT!!!!! I missed the movie
great explanation. thank you
good work
So does it mean it would consume less energy when it is dimmer?
I had this very question today. SO I hooked up a voltmeter to a dimmer and the voltage was around 140vts instead of the measured wall voltage of 120. With an amp clamp on one wire going to a light bulb, I did see a change in amp draw naturally at different settings. So WTF is the dimmer actually doing and how does it do this?
is your meter a True RMS reader?
I have a question; I was playing with a lamp and a dimmer, and i had the suspicion that even with no light in the lamp, there was voltage in the bulb; i conected a testes and no matter the light was on or off, there was up to 100v in the line; coul be a dammaged dimmer or i connected it backwards?? should the dimmer show 0v when its all the way in ''off''?? thanks! :)
ricardo rivera at that voltage the light cannot ignite and stays off.
Not a good idea to connect your testes to line voltage.
I thought you were using Ambisonic audio hahaha
I may have missed it, but does a meter show a drop in voltage? Or does it stay at 120v the entire time?
Yes, the effective voltage your meter would show is reduced. The point of the demo was to show that rather than reducing the amplitude of the full sine wave like an autotransformer or rheostat would, it is done by clipping part of each half-cycle of the voltage sine wave,
Does the circuit use the same amount of power on high as on low?
No, thankfully not. It uses a proportional amount. A little is lost due to heating of the switching electronics. I am working on a new video that will show the differences between different dimmers, such as the one in this video for incandescent lamps vs CFL and LED dimmers as well as fan speed controls. In that I will also talk about power consumption.
Excellent
Well isn't voltage amplitude change as well? You can clearly see that when you slide it.
Alternating current..... I don't get it either
Great presentation, but too bad about the forgotten mic because the audio was so bad it was very difficult to follow.
It's phase cutting dimmer, leading edge
Your not only reducing voltage but light speed, or photon speed because it is less it cannot be seen as far away or "d" distance; and it is a variable of light speed, just like a fires heat, the further away the less heat you feel and less photons reach your eyes, not as bright = displacement, so it is variable or this switch would not work at all in the demonstration.
E=mv^2 or E=mv^3 so, decay rate is variable because if you were next to the Sun the gamma-rays would decay you away fast. Not just the heat.
It also the exact reason we need telescopes to see stars the light cannot reach the full distance to earth without a big boost or magnification of distance with high tech optics or else we could see even a star at two billion light years away.
We need more ideas to lmprove
Could I use this for a standing fan that is 120v to adjust the fan speed ? My wife always complains about being to hot and to cold and I want to add a dimmer switch by the bed so she will stop complaining 😂😂😂 thanx for the video and if you don't have time to answer I also understand.
It is better to use a fan speed control for that application. In the future I plan to make a comparison of the output of various types of controllers. Thanks for the question.
@@FFSeiler Thank you, very much appreciated.
Why light flickering is absent while dimming? The oscilloscope clearly shows the pulses...
The frequency (60 Hz) remains unchanged. It is faster than the human eye can detect flicker in a filament lamp. Also with an incandescent light bulb, the glowing filament dampens any flickering effect even at lower frequencies. It is similar to our eyes perceiving continuous motion even at 24 or 30 frames per second for video.
@@FFSeiler Thanks for explanation, Frank.
I am not so sure your explanation of why that wedge is missing is correct. A triac turns off at the zero cross of AC. What you are seeing is the delay between reading the zero cross and firing the triac.
Is it just me or is he soft-spoken?