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.
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.
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!
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!
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...
@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.
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
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)))
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!
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.
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 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.
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.
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.
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. :)
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).
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
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.
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".
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.
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.
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... :)
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.
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
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.
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 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!
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! :)
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.
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.
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.
Why would cutting off the mains rather than switching it on cause less interference? The change in current should be the same so would generate the same amount of switching noise.
It would be less. The current in a lead phase would allow the load to slowly rise up to the cut off point. The sudden drop off is just current "going away". Add in a series inductor and you can smooth it out. In a lag phase the power suddenly comes on at full power and then drops off slowly. A series inductor would be useless.
Wouldn't the 68n capacitors in the compliant dimmer see the full mains voltage across them if the dimmer switch were on, but with a disconnected load? The triac's MT1 would presumably be floating, so I think the diac would be unable to dump the capacitors' voltage when it would otherwise be triggered?
Oh, I see. Thank you -- I'm used to "load on the right," so I was mentally connecting the load after the triac. In retrospect, that makes no sense and I should have known better.
On the first cheap one, its only 1 way so they advertise it incorrectly. On the second one, I would guess the 0ohm anticlockwise section is for the rotary switch position so it reaches 0ohm before the switch clicks to off?
Kay110 For some strange reason that is how electricians refer to devices, a standard single pole single throw switch is refered to as two way and a single pole double throw switch is called three way. Guess it is because of the number of terminals? The two pole single throw switch used to allow control of a light from three or more positions is called a four way switch and has ..... four terminals!
David V pretty much all domestic light switches are single pole. 1 way is just that, an on off switch. There is no four way switching, you have 2 way intermediates, in which you can have as many switch positions as you like switching the load.
Mrglock Yes, I understand that and agree, but in the trade those switches are called "four way switches" The original comment by kay110 was that the dimmer is a one way (single pole) device, which is true but in the advertisement it was called a "two way" switch which is also true - trades-wise. I don't make these rules, I just try to explain them.
David V I’m in the trade. I’ve never heard another spark refer to them as four way. And usually when people in the trade refer to double pole or single pole, they’re talking about switching L or L N.
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
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.
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.
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.
@@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).
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.
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?
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.
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.
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.
Very odd looking dimmer to US eyes. Do British building electrical system normally attach dimmers (and switches and sockets) to the face plate? US building electrical systems mount the switches, etc, inside the box, and the face plate attaches to the front of the device with a couple of small screws.
@@bigclivedotcom How very odd. Occasionally you'll see wall sockets in the US without faceplates, because the faceplates were removed for painting or whatever, and someone forgot to put the face plate back on. It doesn't matter much since the wiring is tucked behind the device. That said, if someone were reckless or ignorant enough to poke around with a screwdriver, he could eventually find a live terminal.
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
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.
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.
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
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
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.
After my Laser etched was dead on arrival, my 3D printer died after 1 day. But it is still awesome (was printing lots), so I'm swapping the cheepo death dealing ebay PSU for a cheepo death dealling Amazon one. Any suggestions for a 2 output (11A + 5A) 12v + and 12V - output PSU? Just so I don't burn the house down multiple times.
@@CyberlightFG Thanks! I'll also check the "Dads shed" as I think he may have kept a couple random PSUs like that spare (and could even be that brand).
@@CyberlightFG That takes up a lot more space as far as I can tell. As said, 1 rail is 11 amp, 1 is 5 amp. Though looking around I might be able to do it. :) Would an LED driver PSU work? Or are they not the same thing?
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.
I built this schematic in school It was on a breadboard it looks like it was touch sensitive but the board was just crap I still have the video and would upload it if you are interested
I've managed to destroy several dimmers like the better quality one you took apart Clive because mine had standard none resetting over current fuses which got killed by a spike when the tungsten lamp filament failed. Got quite expensive so in the end replaced them with standard switches.
@@bigclivedotcom IIRC it failed 'off' which is why I thought it had taken out a fuse, or at least it looked like a fuse, 10-12mm long, white ceramic looking cylendar, metal caps either end. Can't remember if I put a meter across it at the time. May still have the dead dimmer cluttering up my electrical bit cupboard, so I could put a meter across it now. Thanks for a great video as usual.
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'm not sure why it looks like it goes all the way. I smeared some vaseline on it, closed it up, rotated it back and forth and then saw where it left a furrow. It stopped well short of the end.
@@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!
Anyone know what happened to Clive's Amecal meter. ??? Looks like he's back to the good old trusty Fluke, at least it auto ranges and I'll bet it's more accurate, (maybe a few less low range functions).
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 :)
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.
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.
Given your commentsd about location of the first capacitor after the switch, should then the thermal fuse be positioned after the switch and before the capacitor? Everything I think I know, I've learned from you!
It would have been advantageous to have that extra protection against that capacitor failing in a hot manner, but it's a thermal fuse primarily intended to break the circuit if the triac starts to overheat due to use with a very high load. I'll guess they compromised to keep the tracks as simple and well-spaced as possible.
you could try to turn the cross-head screw-ish blue thing in the middle to see if it stops somewhere (the tit on the metal ring around it might point to where the wiper would be)
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.
"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.
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 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.
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!
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.
I love and really appreciate the way you deacribe the very tiny bit of details. Your content is always very informative and interesting. Love
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.
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)))
Your videos are great ! Always excited when they show up in my alerts !
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!
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?
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.
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.
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.
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.
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 am so pleased its not just me that cannot read resistor colour bands half the time! Great videos Clive, keep 'em coming!
Thanks for pulling your knob off Clive I was really curious what it would look like in that package
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. :)
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).
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
“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!
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.
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".
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.
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
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... :)
I had a dimmer that used the potentiometer body as the core of the suppression choke.
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.
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
old... good audio.....good image.....
and good channel.
I congratulate you.
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 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.
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.
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).
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! :)
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.
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.
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.
Why would cutting off the mains rather than switching it on cause less interference? The change in current should be the same so would generate the same amount of switching noise.
It would be less. The current in a lead phase would allow the load to slowly rise up to the cut off point. The sudden drop off is just current "going away". Add in a series inductor and you can smooth it out. In a lag phase the power suddenly comes on at full power and then drops off slowly. A series inductor would be useless.
I see why what you're saying is intuitional but I don't think it's true. Also you got leading and lag (trailing) the wrong way around.
Wouldn't the 68n capacitors in the compliant dimmer see the full mains voltage across them if the dimmer switch were on, but with a disconnected load? The triac's MT1 would presumably be floating, so I think the diac would be unable to dump the capacitors' voltage when it would otherwise be triggered?
The dimmer is in series with the load. If there was no load the dimmer would not be powered.
Oh, I see. Thank you -- I'm used to "load on the right," so I was mentally connecting the load after the triac. In retrospect, that makes no sense and I should have known better.
On the first cheap one, its only 1 way so they advertise it incorrectly. On the second one, I would guess the 0ohm anticlockwise section is for the rotary switch position so it reaches 0ohm before the switch clicks to off?
kay110 don’t see what you mean - you can turn the lights up and you can turn them down, that’s two ways right? 😄
Kay110 For some strange reason that is how electricians refer to devices, a standard single pole single throw switch is refered to as two way and a single pole double throw switch is called three way. Guess it is because of the number of terminals? The two pole single throw switch used to allow control of a light from three or more positions is called a four way switch and has ..... four terminals!
David V pretty much all domestic light switches are single pole. 1 way is just that, an on off switch. There is no four way switching, you have 2 way intermediates, in which you can have as many switch positions as you like switching the load.
Mrglock Yes, I understand that and agree, but in the trade those switches are called "four way switches" The original comment by kay110 was that the dimmer is a one way (single pole) device, which is true but in the advertisement it was called a "two way" switch which is also true - trades-wise. I don't make these rules, I just try to explain them.
David V I’m in the trade. I’ve never heard another spark refer to them as four way. And usually when people in the trade refer to double pole or single pole, they’re talking about switching L or L N.
one of the first projects we've made in electronic school 👌😉 Smart potentiometer with a safety resistance that the wiper do not touch.
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
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
Showing the output waveform on an oscilloscope would be a nice visual aide to show the difference in these circuits.
Best wishes from Northern Ireland, You got a massive shout from Paul, @ Learn electronics.
Bahut badhiya. 👌👌👌👌👌 Maza aa gaya video dekh k. Kya jordaar explanation di hai yaar. Awesome 👍.
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.
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).
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 ?
The first 1/6th of the pot. It’s like a roller coaster. The first part is really dullsville.... and then the excitement starts!
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.
Thanks Clive you just solved a five year old mystery for me at the 13:30 mark!
So interesting and I learn many thing from you but its better to test both with same lamp and same time to see diffrences.
I wonder if you could scribble some dry erase marker on the track, then run the wiper back and forth a bit to see how far it moves?
I did it afterwards with a smear of vaseline. It stopped a bit further away than I deduced because it has three contact points.
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?
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.
Always a bonus when you can fiddle with your knob
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.
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.
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.
I like the lovely pink base behind your lovely knob :)
The conductive layer is to compensate for the switch movement.
Very odd looking dimmer to US eyes. Do British building electrical system normally attach dimmers (and switches and sockets) to the face plate? US building electrical systems mount the switches, etc, inside the box, and the face plate attaches to the front of the device with a couple of small screws.
Most British stuff is the whole faceplate.
@@bigclivedotcom How very odd. Occasionally you'll see wall sockets in the US without faceplates, because the faceplates were removed for painting or whatever, and someone forgot to put the face plate back on. It doesn't matter much since the wiring is tucked behind the device. That said, if someone were reckless or ignorant enough to poke around with a screwdriver, he could eventually find a live terminal.
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. :-)
I actually guessed the limited physical arc before you cracked it open! :)
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
BTAxx, as used in the eBay Solid State relays
The Hive bulbs get insanely hot - yeah I know it's not related but just putting it out there.
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.
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.
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
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
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.
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..
After my Laser etched was dead on arrival, my 3D printer died after 1 day. But it is still awesome (was printing lots), so I'm swapping the cheepo death dealing ebay PSU for a cheepo death dealling Amazon one. Any suggestions for a 2 output (11A + 5A) 12v + and 12V - output PSU? Just so I don't burn the house down multiple times.
Meanwell
@@CyberlightFG Thanks! I'll also check the "Dads shed" as I think he may have kept a couple random PSUs like that spare (and could even be that brand).
@@TechyBen It may be cheaper to buy two 12V supplies instead of one dual supply.
You should buy identical ones if you need to connect them to +-12V.
@@CyberlightFG That takes up a lot more space as far as I can tell. As said, 1 rail is 11 amp, 1 is 5 amp. Though looking around I might be able to do it. :)
Would an LED driver PSU work? Or are they not the same thing?
Most pc psu's have a high power 5v rail also +12 V and -12V
"I'm going to have to pull my knob off."
Someone phone an ambulance for Big Clive. 😁
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.
I built this schematic in school
It was on a breadboard it looks like it was touch sensitive but the board was just crap
I still have the video and would upload it if you are interested
I've managed to destroy several dimmers like the better quality one you took apart Clive because mine had standard none resetting over current fuses which got killed by a spike when the tungsten lamp filament failed. Got quite expensive so in the end replaced them with standard switches.
Some small lamps are prone to killing the triacs in dimmers when they blow. It makes the dimmer stay on continuously.
@@bigclivedotcom IIRC it failed 'off' which is why I thought it had taken out a fuse, or at least it looked like a fuse, 10-12mm long, white ceramic looking cylendar, metal caps either end. Can't remember if I put a meter across it at the time. May still have the dead dimmer cluttering up my electrical bit cupboard, so I could put a meter across it now. Thanks for a great video as usual.
i for one approve of the extreme zooms.
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
At 19:30, the light is just right so you can see some tracks. It sure looks like it goes all the way to "zero ohms" to me.
I'm not sure why it looks like it goes all the way. I smeared some vaseline on it, closed it up, rotated it back and forth and then saw where it left a furrow. It stopped well short of the end.
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 th-cam.com/channels/MLgHbpJ8qYqj3CkdbvC0Ww.html
@@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!
Anyone know what happened to Clive's Amecal meter. ??? Looks like he's back to the good old trusty Fluke, at least it auto ranges and I'll bet it's more accurate, (maybe a few less low range functions).
The knob to shaft coupling failed. I'll be fixing it shortly.
So to turn on your knob, you rotate it clockwise🤔
but, what's on the back side of the dimmer wafer?
1:05 Just listen, and it’s probably the best double entendre ever.
One of the advantages of having 70 year old eyes, mother nature has provided the dimmer. Maybe I missed it, could the Chinese dimmer cause a fire?
How do I send you something to test
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.
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.
Given your commentsd about location of the first capacitor after the switch, should then the thermal fuse be positioned after the switch and before the capacitor? Everything I think I know, I've learned from you!
It would have been advantageous to have that extra protection against that capacitor failing in a hot manner, but it's a thermal fuse primarily intended to break the circuit if the triac starts to overheat due to use with a very high load. I'll guess they compromised to keep the tracks as simple and well-spaced as possible.
I love your Videos. Thanks for sharing that. Greetings from Hamburg, Germany.
you could try to turn the cross-head screw-ish blue thing in the middle to see if it stops somewhere (the tit on the metal ring around it might point to where the wiper would be)
Hi Clive tell me can you use the joule thief only on alkaline batteries and no other like for instance a cell battery or rechargeable battery?
It should work on any cell of 1.5V or less. It's not suitable for higher voltage because the current can go straight through the LED with no limiting.