Cheap eBay dimmer module vs compliant dimmer. (Schematics)
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- Опубликовано: 23 ноя 2018
- A look at two dimmer modules. One is a really cheap 1 $/£ eBay module and one is a better quality one as sold in the UK for home use. The main differences are in the component ratings and suppression of electrical noise.
I did some more testing of the unusual potentiometer and the resistor section bridging to the middle pin is the fixed 5K resistance that seems to be part of a filtering circuit. The large conductive area is a deliberate dead zone where the knob activates the switch as you turn the dimmer on, and then it gradually decreases in resistance to the point where the rotation is limited at about 29K. Definitely custom-made for the dimmer application.
The inductor will allow low frequency current to flow without much impedance, but will block very sharp current transitions at the switching point.
The most common component to fail in dimmers is the triac, which usually goes short circuit, jamming the load on all the time.
The triac in the cheap dimmer is a PH600E / BT134 rated at 4A if fitted with a heatsink.
The triac in the more expensive suppressed dimmer is a BTA06-600C rated at 6A if fitted with a heatsink.
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Thanks for pulling your knob off and showing us that unusual package Clive.
He had to pull his knob off to get his nut off.
This is just crazy, I was watching on my phone and I was saying: “a zoom will be nice Clive, so I can see bit better on my tiny screen” as soon as I said that, you immediately said “let me zoom in here so people on phones can see better” . Damn you’re good.
I bet that makes you feel good, I mean for me too if that happens I would be happy Like is someone listening to me.....Haha :D
"The excitement of a lamp ramping up and down is not going to be that great"
You really underestimate your audience.
Overestimate, surely?
Yeh would have enjoyed that
I'd love to see both put through the scope just to compare the noise.
I love it when you say: “One moment please” and then immediately come back ;-)
Thank you for so many video’s that are both entertaining and educational/interesting!
Sometimes that simple phrase hides hours of reverse engineering and experimentation.
bigclivedotcom
Oh Yes, I’m very aware of that. That’s why I can’t suppress a mild smile when you apologize to me, while I’m instantly served and you do the hard work. It’s very much appreciated!
It's literally one moment this way!
The two capacitors allow for a longer delay angle. This lets you turn on the lamp at a really dim level right away instead of cranking it up until the lamp comes on fairly bright and then crank it down to a lower level.
According to one of my old text books, the extra resistor and capacitor in the timing circuit are to reduce hysteresis/backlash in the dimmer. Simple dimmers have very noticable backlash going up or down.
Just on a quick note on dimmers.
There are more or less 2 ways of dimming. Cutting away at the leading or at the trailing edge.
It isn’t just that one is more modern than the other but actually depends on where you intend to use it.
Suddenly turning on anything with capacitors in it (LED drivers, electronics etc.) is a very bad idea because a cap acts like a short when first turned on until it has charged resulting in big and sudden current spikes. On the other hand suddenly turning of anything inductive (classical transformers of halogen lighting systems etc.) is an equally bad idea as the collapsing magnetic field will result in sharp and very high voltage spikes. More expensive dimmers can therefore either be manually set or can determine themselves what type of dimming to use. Classic dimmers feature a rating for either RL, RC or RLC which is L=inductive, R= Resistive and C= capacitive loads.
So make Shure to choose the right dimmer for the right application otherwise it won’t live long.
Actually, that sounds far more reasonable than simply "sudden turn-on = BAD / sudden turn-off = GOOD" which makes exactly zero sense assuming a traditional incandescent load, which were the typical things getting dimmed for most of the entire existence of dimmers...
how do you realize sudden turn off with a triac?
@@fredlllll I am afraid for exact details youd have to ask clive. He is far better at explaining this than I am.
Resistance dimming is hugely inefficient.
@pmailkeey That WOULD be the basic principle behind the incandescent light, wouldn't it? Assuming that heat is an intended byproduct. If nor, then they're horribly inefficient.
“Looks like I’m going to have to pull my knob off...”
What the heck did I sub to?
He found a greasy knob shaft too.
@@cabe_bedlam It was also protected from being used too hard.
Gregg Bond BigCliveDotCom REEAAALY likes his dimmers.
You knew what you were getting into.
Aaaaaaand, demonetized!
I love and really appreciate the way you deacribe the very tiny bit of details. Your content is always very informative and interesting. Love
How can anyone not like to disassembly factory electrical products to see how they were made. That is how you learn things. Reverse engineering such circuits always adds to the learning curve. Thumbs Up!
That pot in the ebay module _is_ bespoke for this application right enough !! I've never seen anything like that. The second CR network in the gate circuit of the better controller you showed is there to give a 'double time constant', which removes the 'snap-on' or hysteresis effect you get at low dimming levels - I bought a triac sewing machine foot controller to replace a horrible resistive type, and the new triac one didn't behave properly at low speeds (still better than the resistive one, but...) suddenly cutting in as you ramped it up, so I added the 2nd C/R and the problem went away. I've seen it in older triac dimmer circuits I built back in the 70s.
Dave
Just so. The second CR improves the low range performance.
You might also find a strange looking arrangement with 4 diodes and 2 resistors.
techno-fandom.org/~hobbit/lighting/dimmer.html
I came across that diode one in a Chinese power controller. It took me a while to work out what it was doing. It provides much better symmetry and stability.
Yeah, the 4 diodes/2 extra resistors version seems very popular on the web now - I'm sure it's a better solution to the snap-on effect, but the '2nd CR' version gets you pretty close and only needs 2 extra components rather than 6, and is ideal for the lazy gits like me :o)))
The grease as you call it is a Damping grease,also referred to as motion control grease that makes the pot have a smooth feel to it,infact its the same stuff that old cd player door speed limiters have ,it makes the opening smooth and not rushed.in the late 70's i worked in a company that made dimmers, and the Triacs then had built in Dacs,we had problems with the input caps blowing up every so often,i guess they couldnt handle the mains surges.Love your channel,as a retired electronics engineer,its good to watch.
Your videos are great ! Always excited when they show up in my alerts !
This potentiometer is probably a classic rarity. Shango066 was resurrecting an old CRT valve TV in which the contrast control was mark as 10Mohm with 2Mohm STOP.
I am so pleased its not just me that cannot read resistor colour bands half the time! Great videos Clive, keep 'em coming!
I really enjoyed the comparisons between the cheap Chinese and the compliant UK components. It is instructive to see where they differ but also their similarities. Let's see more like this.
Both are Chinese devices. One is UK compliant, the other is eBay bargain hunter compliant.
Those modules can drive an ignition coil to very high voltages - active to 1uf capacitor to dimmer to coil primary and back to neutral. Great fun if keeping fingers and other parts at a distance. Great blogs with lots of variety. Thanks Clive
Hilarity ensues when you go to your salvaged component tub, looking for a standard potentiometer and grab one of those custom jobs for a project, expecting it to behave normally.
I've definitely had this happen to me.
Can you imagine the amount of salvaged components he must have knocking around. I bet that inductor is now in a box.
Classic sample triac circuit. Right from the included data sheets.
The fancy potentiometer is reminiscent of custom on its in older TVs with multiple taps and custom stops. Smart engineering to save on component count, construction labor, and improve reliability.
Your "brown" is the best one on the internet. But no, i don't watch your videos only waiting for one.
You're so precise and clear. It is really a pleasure to be a follower here. :)
The best piece of advice for anything you wire into your house electrical wiring or anyone else's. Only install certified main stream electrical manufactures equipment. All too often the cheap component manufactures do not necessarily comply with British Standards, Australian Standards or any other reputable authority. Often they are supplied with fraudulent certification and as a result if there are any investigation due to fire or electrical incident you will not be legally covered from prosecution or covered by your insurance.
Richard Kaz An even better piece of advice would be to get a qualified electrician to carry out the works. The amount of botches I’ve gone to where “I haven’t touched it mate, it just stopped working” when it would never have worked in the first place is astonishing. Easy money though so don’t follow my advice ;).
@@mrglock568 Good advice. Qualified Electrical Engineer with electrical and electrical contractor license I've seen some questionable installs by some Australia 457 visa skilled overseas workers to work temporarily in Australia.
Richard Kaz I actually quite enjoy it, it’s fun to see the phrase “a little knowledge is dangerous” in action!
pmailkeey Priceless. So clueless on the lengths it takes to become fully qualified it’s almost funny.
pmailkeey You honestly should stop while you’re ahead. Messing with gas supplies and repairing them with blu-tack (I can’t believe I’m even typing that)? You’re honestly a danger to yourself and others around you, you’ve been incredibly lucky so far, soon that luck may run out. Typical botch-it DIY man who thinks he knows better than qualified professionals.
I kinda didn't really understand anything you said but I think I might have learnt something and maybe one day I'll find out what it was. Love your videos, they are mesmerising! Take care, Poo
Thanks for pulling your knob off Clive I was really curious what it would look like in that package
Best wishes from Northern Ireland, You got a massive shout from Paul, @ Learn electronics.
Might be worth hooking these up to your scope (so we can see just how noisy the non-compliant model is). The alloy pot knob on the Chinese version would cost more than the entire kit in Australia! Those cheaper Chinese pots often benefit from a quick squirt of contact cleaner (reduces noise, seems to extend useful lifespan).
Dimmer switches are the bane of my life. “Hello sir, will this switch work with this component?” “Yes sir, this switch is designed for you application “. Never trust a sales man
When I was in retail sales, I would respond, "I'm not sure, I've never tried that switch with your particular setup." I would then often watch them go over to some other sales person who would tell them, "Yes, sir, that will work perfectly," and get the sale (often followed a few days later by the return of the item). Many people seem to want a positive answer, even if it's incorrect.
So how the heck do you manage to get a pink potentiometer? 2:42 In my 40 years of experience I've never seen a pink one.
old... good audio.....good image.....
and good channel.
I congratulate you.
Bahut badhiya. 👌👌👌👌👌 Maza aa gaya video dekh k. Kya jordaar explanation di hai yaar. Awesome 👍.
Recently bought some Chinese electrics for AliExpress (putting some LED strips up in the non-mains connected garage). The '20 AWG' cable and '240v' inline switch were very clearly not to spec, but work perfectly for low voltage DC projects! :)
The first 1/6th of the pot. It’s like a roller coaster. The first part is really dullsville.... and then the excitement starts!
Ah dimmer fun :-) Finally found something that does dim my dim able leds. After some 'special led' dimmers, got some remote controlled stuff. Same 6 leds, but now I can control them without flickering. It also does a nice range.
It's been a while since I last used a dimmer, I think they pretty much lost favour when CFLs took over (and I did have a dimmable CFL at one point, 'til it failed to dim properly and just worked as a "normal" CFL), now I just adjust my lighting by changing the bulb for a lower lumens LED lamp... :)
one of the first projects we've made in electronic school 👌😉 Smart potentiometer with a safety resistance that the wiper do not touch.
The 0 Ohm non resistive arc is where the on off switch actuates. maybe to reduce arcing and wear on the resistive track at switch off?
Isn't it more like max ohm before ramping down?
I have seen a few that have integrated the diac into the triac as well, one less component to place on the board, allowing them to make it smaller as well, small enough to fit into an in line dimmer and only have the case barely bigger than the linear pot used for control, which also has the resistive patterning to put the rest of the resistors on there and only has a small mylar capacitor. Generally the triac also does not have a full tab on it, often using a thinner sheet as well for the die mounting, though I have yet to see one with integrated diac that is fully insulated, those are very common though and you find the triac held to a small aluminium tab as heatsink using a rivet.
I believe they're called quadracs.
That triac should be 600 V, 6 A, if they're using the same nomenclature as on devices I was making in the 1970's. That generous rating should be a cheap way of giving some protection to the device when connected to the inductive load. Fun fact: If the dv/dt rating of a triac or thyristor is exceeded, it tends to shatter the device so that a terminal becomes disconnected whilst still being attached to a saucer-shaped piece of the Silicon surface. Seeing that, when inspected, is clear proof of how the device was abused. Thanks Clive.
I like the lovely pink base behind your lovely knob :)
"I'm going to have to pull my knob off."
Someone phone an ambulance for Big Clive. 😁
Solid section on variable resistor is because this is designed to work with the switch, It's so when you switch on the resistance wiper starts after that and not before. ie it always turns on at a designated resistance. Without this it would be hit and miss what value the thing was at when the switch part triggered.
I love your Videos. Thanks for sharing that. Greetings from Hamburg, Germany.
So interesting and I learn many thing from you but its better to test both with same lamp and same time to see diffrences.
Would have been interesting to hook-up the cheepo dimmer to a scope and see how 'noisy' it really is....I still think Clive has the next most soothing voice after Bob Ross.
I actually guessed the limited physical arc before you cracked it open! :)
Thanks Clive you just solved a five year old mystery for me at the 13:30 mark!
Thanks for considering phone viewers.
I still have the first dimmer circuit I ever made from the International Rectifier data sheet. Used it mostly to control an electric blanket.
A) Do you still use the dimmer?
B) Do you still use the electric blanket?
@@TCGProductions03
I still have it, but haven't used it in a long time. I had to move suddenly, and threw out much of my possessions, including my electric blanket. I have been thinking of getting a new one. It might save me some money if I can lower the room tempature (electric heat is expensive).
If you look at the datasheet for the MOC3010 (I have the Fairchild one on my web site and here), they show the extra R and C being used "for inductive load".
Your video’s not only make me understand electronics but also David Coulthard.
Pardon?
Twotone Scottish pronunciation.
@@Conservator. Sorry, it was just a silly joke, you say you understand so I say pardon :)
Twotone Haha, Then I’m the one to apologize 😂
@@Conservator. You have no need to :) We're all friends here. Anyway it was always a risky comment on my part.
I had a customer come in with a small 230-110V power converter that had stopped working. I checked it out and it was made with the same type of triac as that dimmer. He ran his rice cooker on it!
They're common, but only really suited to simple resistive loads. I took one apart in a video a while ago. (It had melted).
I think the two capacitor idea is to make the dimmer more tolerant of non-sinusoidal mains. If you look at the mains with an oscilloscope (be careful with voltage ratings if you try this), it is quite variable and far from a sine wave. The "first" R/C network forms a low-pass filter designed to remove some of the high frequency components of the mains waveform. The result should be a more consistent light level regardless of other loads on the network. It would be interesting to investigate this.
wont work properly withMSW anyway
You don't want to get power spikes to the shaft with all that grease on it....the knob could blow
Aha nice video,I learn a lot( on a serious note ) , subscribed
ahhh Clive been on your channel age's av just sussed out how to send replies i could not get them to send it was my pc anti virus scanner not letting me so hello love watching these keep them flowing the more the merrier 10/10
It's a neat idea, trimming the carbon track like they did, but I do worry that the sliding contact will eventually begin to pull up the trimmed edge of it, and cause physical malfunction. Seems silly when resistors are practically free.
Would it be possible to explain the difference between the standard filament dimmer and the LED dimmers is it just LED trigger on leading edge ?
Thx. Enjoyed. For contrast any chance you can reverse engineer a V-PRO trailing edge (LED) dimmer? Just looked at a popped one of mine and interestingly seems to have no filtering either. Assume the dead component is a MOSFET.
Interesting timing, I just got a bunch of packages in the mail from Home Depot with the new toggled brand dimmable 4 foot LED lights. Can't wait to see how well they dim.
Enjoyed that. Any chance you could power up the cheapo type and one with interference suppression and compare the RF noise, perhaps on a 'scope or an AM radio?
I had a dimmer that used the potentiometer body as the core of the suppression choke.
As soon as you said you had to pull your knob off I knew the comments section would be filled with crude humor, I was NOT disappointed. :-)
Clive and Fran sitting in a tree,
Checking for components contin-u-ity.
Seriously though how cool would it be if you two did a collaboration.
Fran truly needs to move to the Isle. That would be so awesome.
@pmailkeey Frans Lab ruclips.net/channel/UCMLgHbpJ8qYqj3CkdbvC0Ww
@@jamesplotkin4674 In these days of the Internet and transatlantic telecommuting I don't think she needs to move anywhere really!! :-) Unless of course she can grow a beard and join the Manx Beard Club!
@@AAAyyyGGG Actually, Fran is being forced out of her present home and moving in, or being near Clive would be such a hoot!
I recall from the old RCA manual (1960?) that the 2nd capacitor allowed the dimmer to dim to a lower level by "replenishing" the trigger capacitor. It seems that the trigger capacitor didn't have enough charge at extreme dimming levels.
The single capacitor phase angle trigger has a huge hysteresis Half brightness on the way up is different from half brightness on the way down. The two capacitor circuit improves on this til 50% level may be half of knob travel up or down
Always remember to re-grease your knob, after pulling it off.
Or beforehand, as the case may be.
That additional capacitor in the compliant dimmer may be an effort to reduce the hysteresis effect inherent in the basic dimmer design. The hysteresis, sometimes called snap-back or snap-on, is seen when slowly turning up the brightness from a lamp-off condition. At some point the lamp will suddenly turn on at an intermediate brightness level. The brightness can then be reduced to a lower level.
A much better method to reduce and actually eliminate the hysteresis effect is to add two diodes and a resistor. It's generally very easy to do and I've modified many low cost dimmers this way to improve their operation. Take a look at Teccor's application note AN1003 for more detailed info.
You could probably put that rheostat back together using some epoxy. It looks like British light switches always use double-gang switch boxes. I guess. It's probably something else altogether. In America, a double-gang box allows you to but two switches or receptacles in one box. They are also used for high current 240v receptacles like electric clothes dryers. It's kind of funny our plugs don't have insulated prongs. At least, we aren't still using knob and tube wiring.
With the UK switches the plate and the switch is one piece, and you can buy 1,2 or 3 gang switches which all have the same size plate, so they fit on the same box.
I have an 18Kw water heater (tankless) that uses Triac's to 'Modulate' the power. While my home has pretty good wiring it still adds a nice dip to the mains while running. It's more or less an 18Kw lamp dimmer heating water. If it didn't do it's job so well I would get rid of it.
16:35 spinning barrel rivets. Move the drill to a 30 * or so angle and keep drilling. The flutes will nibble at the rolled part of the rivet.
TNX 4 another great video !
I wonder if there's resistance in series with the wiper contact too. It looks like there could be. Easy enough to find out, just measure from the wiper terminal to the wiper contact ring.
Good video Clive
phase cut dimmers are horrible. Built a few in my time but with modern electronic lighting they just don't work because electronic loads don't have the current through them required for the dimmer to work, unless you have a separate neutral reference which you simply don't have in domestic lighting circuits at the switch. Electronic dimmers like the one mentioned near the start is what you need, but these use FETs to switch the current. Much prefer DALI dimmable control gear.
Is it odd that when he pulled on his knob to reveal it's pink shaft I got excited to see what was next?
You can use a 3V coin cell battery to trigger the triac using a opto-diac. eg MOC3021 . If doing the scratchy test on one of the terminals of the battery ( using alligator clip wires) watch what happens to the bulb :P yeah disco lights. Nice AIO potenciometer
Children, cover your eyes. Clive said he was going to pull his knob off.
Showing the output waveform on an oscilloscope would be a nice visual aide to show the difference in these circuits.
I did use one of the wall mount ones on an energy saving bulb, very quick way to make a strobe light, useless for use generally 😂 wonder if you could modify them for led and ccfl
i for one approve of the extreme zooms.
I love your videos big Clive ☺☺☺☺
This was neat!
would it be nice to have a multi spectrum LED light..trying to see colors when you are using 1 or a Narrow spectrum is a pain..
Hey Clive, is there an easy way to modify one of these so that when connected it ramps up from 0% to 100% over a second or so? I want to prolong the lifespan of some old tungstan filament lamps used in a display cabinet as I can no longer get the bulbs. LED conversion is not an option because they are tubular lamps and need to illuminate all the way round. I know I could just manually advance the pot but they are remotely switched by a timer. Any ideas please? Thanks.
Not so easy with a standard dimmer. You could maybe add a series NTC inrush limiter to take the edge off the switch-on.
Great explanation but could you show the 2way element please Clive, ie the third terminal
1:05 Just listen, and it’s probably the best double entendre ever.
Interesting and educational
Yes! Finally a BC video with greasy knobs instead of fairy lights... :-)
Dedication is watching big clive with a massively cracked phone screen especially when he is drawing schematics so many lines to see...
Hi, love the videos. could you due one on the led 0-10 volt dimmers. they cost way to much. all most the cost of the light ???thank you
Very interesting - thanks!
Wish i could afford to send you a Logitech smart dimmer from Australia. Makes those look stone age.
Is there a way to improve these so that at the minimum sweep the light is lit, but only just? I have one where the light is out before the end of the track and could do with a modification.
Thanks in advance.
Which dimmer are you talking about? In any case, you should be able to tweak that by adjusting the value of the resistor in front of it (like the 100k one at about 8:00). Only right now I can't figure out if you need a larger or smaller value :D If it turns out you need less resistance, you can just whack on another one in parallel, leaving the original one in place. Otherwise you need to put one in series and thus disconnect the original one on one side. Of course any such mod would make YOU responsible in case it goes ka-boom :)
@@han5vk Thanks, that sounds do-able then, at my risk of course...
Lower the resistance to make the dimmer dimmer. Does that make sense?
It might be easiest to try another dimmer and see if it has a better range. Keep in mind that electronic lamps rarely behave properly at lower intensity levels on a tungsten dimmer.
Always a bonus when you can fiddle with your knob
I have a very old Soviet made 600W 220v drill.
I wonder if it is a good idea to connect the 1st cheap dimmer with it?
It's the only dimmer module available at local market in my city.
Any advice?
It would benefit from a snubber network across the triac to protect it from the inductive load and make it more stable. Most drills are based on universal motors, so it should work OK.
Well there's our Clive, tugging on his knob.
I yelled NOOOO in my head when you didn't connect the wiper
Hey Clive,
I have seen a make your own retro camera advent calendar in Debenhams that I think you should test out,
it would be really cool if you could make a video on this for me,
thank you
Yoy have a parallel resistance between the left and the middle pins. So your potentiometer has a logarithmic behavior, what makes perfect sense, because that will provide a smooth transition between low and full power to the load.
What about those fancy Varilight ones with programmable modes for different loads? Do they use a microcontroller with some sort of transistor and PWM?
I'm guessing they probably use the lagging edge dimming to minimise current spikes to the LED circuitry.
The Hive bulbs get insanely hot - yeah I know it's not related but just putting it out there.
Sorry to bother Clive, butt I was wondering if there's any way that it's possible to stop a transformer from "singing" once it starts. Some very good LED bulbs have started doing this, making them essentially unusable.
Depending on construction and cheapness they may be missing entirely their dose of standard spar varnish to tie up the windings with. This also keeps them from moving relative to the core in better built transformers. Time is needed for the spar varnish to cure though.