Inside an electronic halogen lamp driver, with schematic
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- Опубликовано: 28 сен 2024
- It's taken me a while to get around to looking at one of these things. It's a compact electronic power supply that takes mains voltage in and puts out a rough equivalent of 12V AC.
I say rough equivalent, because the output consists of a 100/120Hz modulated high frequency hump with spikes in the region of about 30V that average out to 12V as seen by a simple tungsten load.
LED lamps may tolerate being connected to these things, but may suffer damage. I always recommend using 12V DC LED drivers for your 12V LED lamps.
These units will not operate correctly if under-loaded. They require a minimum current to ensure stable oscillator start up on each half wave. If replacing lamps in ceiling lights with LED and they suddenly start flashing and flickering as a group, there's probably one of these involved. The fix is either to replace one or more of the lamps with tungsten ones again to provide a stable load, or to swap out the power supply for a 12V DC LED driver - which is the best option.
Because these units "ride the sinewave" they are dimmable and also have near unity power factor as the current is spread across the full sinewave.
It's best to avoid using these electronic transformers on the same circuits as traditional magnetic ones, as the switch-off voltage spike from the transformers may damage them. It's also best to avoid placing them where they will be covered with thermal insulation, as heat is an issue. They have a history of going bang. In the long term, a traditional properly rated core and coil transformer will outlast these electronic supplies by a huge margin.
The start up circuitry in this unit is odd. It looks like it relies on the rising positive voltage to pass a controlled pulse of current through the 10nF capacitor when the diac triggers, and then relies on the low impedance of the start transistors base circuit to avoid accidental triggering with noise.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.co...
This also keeps the channel independent of RUclips's advertising algorithms allowing it to be a bit more dangerous and naughty.
I learn so much practical electronics from you. I’d never even get halfway to working out how this circuit works.
I agree, he's very knowledgeable and does well explaining everything imo.
Agreed.
I find his voice very soothing.. relaxing.. easy to listen to for hours.
I love the way you broke out the rectifying diodes in the schematic, i'm stealing that.
You have provided me years of enjoyment in your videos. Your the only reverse engineer I know on RUclips. which makes you the best!honestly I have no words of improvements.and if you dropped off youtube I’d cry.
Just thought you needed to know that.
AVE does quite a good RE video.
DiodeGoneWild is also excellent, he knows a lot.
You forgot to mention that the main advantage to the electronic drivers is their efficiency compared to traditional transformers.
And thumbs up for a CFL video.
Would love to see some tear downs and RE of the different types of Fluorescent light fitting ballasts
@Dave Micolichek Doesn't really matter how efficient the transformer is if you use it to drive something that wastes 95% of the power as heat. A 99% efficient transformer with a 100W load will waste the same power as a 90% efficient driver with a 10W load. Incandescent bulbs are atrociously inefficient and the fact we allowed them to keep existing as long as they did when we had fluorescent lights is a disgrace.
@Dave Micolichek That's incorrect. High frequency switch mode power supplies are far more efficient. They may last longer, but are more expensive to buy and operate. SMPS are used in virtually all modern electronics for good reason.
Chris W - the efficiency of a conventional transformer depends on its construction, the quality of materials and it’s size. Good quality conventional transformers can have a full load efficiency between 95% to 98.5%. Show me a cheap switching power supply that can do that...
@@Mark1024MAK A cheap 60 Hz power transformer is not going to be 95% efficient either. Good SMPS are 95% efficient at full load. For DC regulated supplies, the advantage goes to SMPS hands down. A 60Hz transformer supply is around 40% efficient with linear regulation. A boost or buck converter can be used to increase that, but thats switching technology and if you're going to use switching, a full SMPS topology is best. I haven't seen a 60Hz transformer in professional video equipment in over ten years.
"Wonder what all these holes are for in the enclosure. Oh well."
> Sticks "OK-QC" sticker over as many ventilation holes as possible, instead of the end panel that's solid.
Never change, china.
Just like the PAT tester plonks nice lovely layers of tested paper stickers over ventilation holes and on plug top power supply units.
I love your videos! The old school "pen and paper" method is priceless. It also gives you the ability to produce a video much quicker, and you still get the point/information across, rather than spending more time doing all the fancy graphics that are not so important in my opinion. I love it! Keep it up!
Couldn’t agree more!
I like the capacitor arrangement in this version. It makes for a quick start as the voltage over the DIAC increases immediately with the input rising. The resistor in parallel just ensures the cap is discharged again.
But indeed, spike sensitivity...
My Fluorescent tube electronic driver went the other day. I opened up and saw the two small electrolytic capacitors are dead (swollen top).
I remember my 2nd house having electronic drivers for the living room halogen lights (hated using those things!! Rented property sucks when they put crap like that in!) and, yep, they went bang, under the floor of the room above, making it smell really nice in what was then my bedroom... :S
I hate it when people seal these things off in inaccessible areas.
@@uK8cvPAq It’s probably illegal, too…
Talking about this type of device making a good radio jammer, my first audio amplifier was very good at picking up radio Moscow world service...
For us it was the infamous Radio Peking. I do not know what was the transmitter power, it it was good enough to be picked up by a no transistor single diode radio (no power needed to hear)
with all the effing graboids idk how you have time to even listen to a radio
Was it a Clive Sinclair one by any chance? DC-100Khz... lol!
Thanks for explaining this. I took one of these out of a vintage makeup lamp. It has a large capacitor and inductor for smoothing and two 1N diodes where the diac would be. I didn’t know why they convert AC to DC back to AC again, but then I learned about the need for feedback, isolation, and dimming. I enjoyed your explanation of the double crossover circuit. Now know there isn’t much use outside of driving a halogen bulb. Maybe it is useful for parts!
Please do take a CFL driver apart
Thank you for your every video. Since I started watching your channel (and Louis Rossmann) I've learned a TON. Before, I was quite anxious to component level repairs - now I do lots of it, diagnosing problems, detecting faults, following my typical approach - even if it's not really worth it, I'll do it anyway :D
When I started my work in maintenance department at my company, there was a lot of automation equipment no longer functioning properly, being instead operated manually. Timer relays for lights, phase sequence relays, stuff like this. After watching your videos, I started to understand principles of capacitive power supplies. Now I brought most of it back to life thanks to you. Granted, I could've just buy new components and replace them, but where's the fun? Also, replacing them would mean utilisation of old parts, so you essentially prevented generating of more electrowaste :)
Thank you, Clive! Greetings from Poland!
Classic Resonant supply Topology . Pretty cool use of the design
Very nice to see a Swiss vintage Knobel Transformer. I did not expect to see any outside in UK or EU.
I was browsing the old bowl tech forums when I saw a familiar name. Crazy small world. I was active on there quite a long time ago but still work in the bowling industry.
I think I remember your name from that forum. I find pinsetters fascinating.
@@bigclivedotcom I was looking up if anyone had been able to use a different camera on a specific scoring system and just happened to notice a familiar name talking about it also. Need anything bowling related hit me up.
The RF emissions and susceptibility of this circuit to mains induced spikes both explain why there was a big fat suppression cap across the AC input!
You know what you have to do now Clive, don't you? We need to see an LED go bang in your next live stream.
I want to see an LED go *BANG!* as well. :-)
Unfortunately they don't go bang ... they just ... stop.
They used to occasionally bang when run without a ballast resistor. I remember my father soldering together a whole pack of random LEDs from RadioShack in the late 1970s and then attaching them to an electric train transformer. One of the LEDs exploded loudly.
@@phoenixdundee And become DED's - Dark Emitting Diodes....
@@phoenixdundee Not always...sometimes they explode quite violently -- but yes, they often just let their supply of magic smoke out (it's rather stinky!) or simply extinguish silently and permanently. But again, some of them do go out with a bang. :-O
I thought I would save my company some money by replacing 12 halogen MR16 lamps (in reception area) with LED versions, but I specifically got the LED version that said was compatible with electronic halogen drivers. Well it started out ok, it worked fine until after about 3 months the first LED died, then another, then another. After about a year just over half of them had failed. Each time I replaced the LED, I also replaced the driver with a proper LED driver. All the LED lamps that were on LED drivers never failed.
I once tried to add bridge rectifier made from schottky diodes to one with smoothing cap as well, it did not like it one bit and over heated promptly.
After the CFL lamps were replaced by LEDs, I thought, great! Now we're finally getting rid of that stupid CFL circuit that dies before the tube dies. And then I find that that damned circuit is still around in halogen lights! 😠😠The CFLs have two of those cheap light duty transistors in the TO-92 package. The first unventilated lamp it's screwed into will cause it to overheat and then like you said, go bang. Really lame.
Thanks for the informative video, Clive.
Interesting wave form. Curious the power factor of the other more substantial inductive driver.
It looks like amplitude modulation of a HF signal by mains power.
@Leonel Yser By being a Patreon supporter and, in exchange for paying Clive a monthly stipend of a few dollars, getting the chance to watch this and other videos early.
@Leonel Yser Highly recommend becoming a Patreon supporter!
Where would these be used? Most of the halogen bulbs over here just connect right to the 120vac mains.
There were 12V Halogens, quite trendy for a while.
See here:
www.brewstersbatteries.co.uk/catalog/premierrl1205h12v5wmr11halogen-p-575.html
The higher voltage halogen lamps are less robust, less efficient and can explode when they fail. Especially on 240V.
@@bigclivedotcom I once saw an old project online where somebody put 20 low voltage 12v halogen bulbs in series to run directly off of 240v. I thought it was a neat project.
I'm sure you know what website this was on :)
@@eDoc2020 Sadly I can't use my deadly chandelier here. The ceiling is too low.
I tried a 20-105 W electronic halogen transformer witha 10 W lamp and it worked. If it power a 5 W lamp its lit dimly. The miltimeter cant measure the HF AC output so I used a diode and a capacitor to measure peak voltage. With no load it was about 6 V in 1 direction and about 12 V in the other direction. With a load its about 17 V in both directions.
It would be great if you would have give the number of windings of both the transformer and the feedback coil. :)
Have you seen these in 6 V and 24 V verisons? They sometimes pop up on online sales, 6 and 24 V halogen downlights seem much less common than 12 V ones. 32, 36, 42 and 48 V spotlights are so uncommon that even the classic iron core 50 Hz transformer is hard to find.
It might be viable to rewind the outer secondary on the toroidal types for a custom voltage.
I made a tiny tesla coil with one of these many years ago.Well not a tesla coil I just fed the High frequency ac into a salvaged TV Transformer. It made nice sparks.
Thanks for this vid. I got the flashing issue when I replaced halogen with LED.
I wonder if you could get it to print on the other side of the paper. and then cut it out make it look like an actual circuit board just flip the paper over.
Are you sure the transistor stays on until the capacitor discharges? It looks almost like a blocking oscillator where the feedback rapidly changes polarity when the transformer core saturates.
What would happen if a 400V electrolytic capacitor was added to the rectified mains DC. Would the output be less "like a string of beads" or would the transistors go bang. Would adding an LC filter to the spikey 12V AC output make any difference to the high voltage spikes.
That's what compact fluorescent lamps do. If it was done to this unit the output voltage would be higher and it would not be dimmable.
Hi
Is the little transformer in the PCB an ordinary 50/60 Hz or it workes on higher frequency?
Waiting for your highly informative answer.
It's custom wound for higher frequency.
@@bigclivedotcom
Thank you so much for your reply.
QC sticker is a classic.
Thank y sir!
It's possible use this for drive a little neon tube at 12v?
For the science can try?
This won't work for that, but you can get 12V neon power supplies.
Thanks again😀
What does that spiky waveform sound like? Would there be a way to generate it with lower voltages and/or without the risk of the circuit blowing up?
Clive on the larger versions of these, are all these components just scaled up or does it have extra protection?
Some just scale it up, but most add short circuit protection.
Larger versions can be made cheaper and better performing with slightly more complexity. You can scale up this basic circuit but it’s not terribly wise. Also, today you can have a $0.10 microcontroller running the show in those supplies and it can do a much better job at controlling it all than a raw BJT self-resonant converter.
Good to see "CliveCad".....
I replaced the halogen lamps in our kitchen track-light with LEDs - it didn't end well.
I would like to buy drivers
hi big clive . could you explain how a vw electric power steering system works . i took one apart its very instresting cos it seems to use a brushless 3 phase mlotor some how worked from 12v dc power supply hope can explane this . thanks
I would really like to see a teardown/explanation video on that also! I'm glad they use brushless motors in the VW ones, as steering is pretty important (!) would hate to have it fail because of a brush/commutator mishap!
When it fails you have manual steering yet
I just saw something on ebay you might be interested in, its a 1kV megger/insulation tester that sells for 15 quid brand new, model number BM500A
I have one here. The problem with using it in the UK is that the red tape brigade would frown on it for not ticking their boxes.
please make a video about CFL drivers with schematic
Very interesting. Super !!
why don't they just drive the lamp from full wave rectified 12v off the transf secondaru and dispense with the rest?
Because for the equivalent power at 50/60Hz the transformer would have to be much bigger.
"Operates at ridiculous frequencies of 30Khz" as a RF guy.... "Ridiculous" is some place above 60 Ghz because that is the limit of the spectrum analyses I have access to goes.
60GHz being a particularly interesting frequency. (Oxygen attenuation).
@@bigclivedotcom the crazy High stuff is what you find in military Electronics I think that they top out at 110ghz
@@bigclivedotcom Yep. 60GHz absorption is what radio astronomers can use to look for oxygen :)
This is off topic but I was wondering if anyone knows how to adjust the temp on yihua 939d soldering station?
Nice video. Recently I opened an analog strobe light because it wasn't working. The circuit is pretty similar but there is a component named LD1 that looks kind of like a mini halogen with two little pieces inside similar to coils. When I turn it on, one of the sides in the LD1 gets bright (with kind of an incandescent look) flashes at the freq the halogen strobe light should be doing but the strobe doesn´t work. Anyone knows what that is and how does it work. I've been searching for information but most of what i found were digital strobes. Any information would be nice thank!!!
It's probably an NE2 indicator lamp being used as a voltage threshold trigger.
@@bigclivedotcom YESS that's the exact component, thank you very much, i will try to put a new one. I'm a student in electronic engineering and your videos are helping me a lot to get motivation, so thanks x2.
@@perlyax When the neon flashes it will probably trigger a thyristor that will dump the charge on a capacitor through the primary of the xenon tube's trigger coil.
@@bigclivedotcom Yes that must be, I will take a look at it and see if I can revive the strobe and hopefully learn new things, thank you!
Arghhh! You didn’t draw the Full Bridge Rectifier in a diamond shape! Must be a first in the electronics domain?
It would be interesting to get some HV probes and an isolation transformer and scope things like this?
I have a really early General Electric SCR manual that has the diode bridges drawn this way. 1962 I believe is the publication date. Therefore, I always draw full wave bridges that way. Guess it's the way you learned as a kid.
Have you seen the new Poundland Halloween LED fairy lights?
I've not been there for a while. I'll have to get in.
I have - had - 12v halogen lights in my bathroom. As the bulbs blew, as they do, I replaced then with LEDs, which didn't work. Assumed the drivers had died. Might be they are these, and just wanging some halogens in will have them working again.
I feel rather stupid now 🙂
It's a common thing. It catches a lot of people out.
@@bigclivedotcom if it is just the bulbs, my brother will kill me - I had him go up into the spider invested loft to make sure the drivers were getting power.
He hates spiders 🤣
Who else thinks Big Clive should make some ASMR videos just for shits and giggles? masticating noises alert!!🤣🤣
Clive how do I send something to you? I have the black box off my car that might interest you
I have one here in the video pile.
Hi Clive, Do You Have an Address So That I Can Send You Something that I Hope You Can Find and Fix The Problem....
MANY Thanks
Yay another video
My tablet corrected my text just before sending. VA and PF
If you had drawn the main transformer slightly more to the left the right hand side of the schematic looks a little bit like you with your glasses on 🤣
Use it to drive a flyback trans!!! Just keep DMM's far away!!!😱😱😱 I killed 2 DMM's, one right next to the flyback and the ²nd 3feet away!
Nice...Oh Maybe not High Noise...lol
Hi man!
Recover the table! 😂 Its a bit damaged by Your mishaps....
Soon as I saw the top right of the circuit diagram instantly thought is that an electronic version of Kilroy/Chad, often associated with Wot No.... minus the long nose.
LOL... "these PEAKS of output" ...look like a sketch of a bra from the top and from the front! :)
Can please say Sine Wave and not Sane Wave? Say Road Sine!
Seriously???
You are Physically watching a RUclips channel with someone from a country other than 'Murica, that actually knows how to pronounce words "Correctly".
I realize this may come as a shock to you, but even though the Scots and Irish have their own dialect, it's far closer to English than anyone speaking' Murican, as this is probably what you are used to hearing.
Taking into account that it is possibly 'You' that is the problem, maybe, instead of whining about Clives dialect, you should find a channel more suited to your taste, or lack there of?
Don't you hate this sort of shitty SMPS PSU. No mains input common-mode filtering. Total junk!. Broadband radio-frequency noise sourse.
BS Standard == Bullshit Standard?
Whenever I hear 'Bridge rectifier', I either hear AvE's Rectumfrier, or with echo, "FULL BRIDGE RECTIFIER" Electroboom style with flowing monobrow.
I saw the waveforms and my first thought was of the Arctic Monkey's video for "Do I wanna know?"
"If this feeling flows both ways?"
Hi Big Clive. I've just reverse engineered a halogen lamp driver from a fancy light fitting so I can repair it. One of my viewers then posted me your video. The one I looked at is much like yours but it has over current and over temp protection. You can find it of you look for How to Identify the Blown Components and fix it CONTINUED. Feel free to pop over and say Hi if you like. Richard.
It does not discharge the capacitors in its HF half-cycle. The driver transformer core saturates first, and that makes the transistor base current stop.
@Dave Micolichek Core saturation will cause the transformer coupling to vanish, as the magnetic field strength can no longer change. Primary current will no longer be transformed.
Would it be safe to say that the quality control label applied over the ventilation holes does, in fact, control the quality?
New subscriber:
xraytonyb gave you high praise and made reference to your channel in his video RUclips titled "Random Comments - 9-5-2020"
Just as I was going to mess with a couple of these that I have, Clive does a video on it. Weird timeline.
Noisy but interesting circuit. Thank you Clive !
Your printer is amazing your prints look so real
Timsalt3100 It‘s not the tool. It‘s the carpenter.
@Mai Mariarti I may remember he talked about an epson with ink tanks. Could be wrong...
@Mai Mariarti The ink tank printers are very cheap to run. £30 for 6000 prints ... approx.
@Mai Mariarti. Clive mentioned the printer in one of his earlier videos, I'll find a link for you... Give me a bit of time, my granny just passed, so I am busy arranging funeral stuff 😢
@Mai Mariarti He uses an ink printer that has been modified with a continuous ink supply system (CISS). I use an Epson EcoTank that does much the same.
It's looking like a electronic CFL circuit with push-pull / half bridge configuration.
"ridiculous frequencies... 30kHz..." bwahahaha!
(ham radio guy here)
At least the second harmonic is good for annoying teenagers and people like me nearing their 40s that can still hear all the way up to 18ish khz.
I went for an interview at a company named RF Microdevices a couple decades ago. They referred to 100 MHz as "essentially DC."
@@sivalley You mean subharmonic. The second harmonic of 30kHz is 60kHz.
@@misterhat5823 durn typo! You got me Mister Hat! How is Mrs. Garrison and Mr. Stick? 😄
2.751oz Clive 😂
I think your lighting technology videos are your best. Your years of practical experience with lighting enables you to make very insightful comments about how the technology actually works in use. These videos are why I subscribed, and also inspired my design of a light probe to measure lighting output waveforms. Thank you.
I think the resistor/capacitor/diac combination in the first one essentially does the same thing. The resistor helps trickle some current around the capacitor on the rising edge of the rectified wave to keep a voltage bias across the diac so it will trigger. Once triggered, it connects the lower side of the 10nF capacitor to the base of the lower transistor, and then ground, which begins to charge the capacitor and provide a trigger pulse to the lower transistor to turn it on. Once the capacitor has charged, the current pulse ceases, but at that point the feedback network will have taken over and begin oscillating. Theoretically it saves them a diode since the 18k should keep the lower side of the capacitor hovering about the midpoint of the switching waveform, and keep the diac off until the end of the rectified wave at which point it will discharge thru the 360kOhm resistor, if Im reading it right.
What’s the advantage of this over a 12v SMPS?
Dimmable and very high current in a small space.
bigclivedotcom Thanks. I get the dimmable bit but why higher current?
@@michaelfisher9671 No smoothing or regulation required.
@@bigclivedotcom Thanks for that.
Cheap
Interesting stuff ... having done a large halogen to led swap I remember the issue about not having enough load to keep a circuit active, but your comments about the rough waveform probably explains the high dropout rate. Fortunately the power savings were massive compared to the cost of the bulbs so nobody even thought it odd. Thx Clive!
Clive, could you do the same for what's in a high frequency electronic fluorescent tube ballast?
I've been falling behind on your videos as I binge watch tv shows.
All the same, I hope you're doing well, and soon I will binge watch your videos and get caught up. =D
As a child/teenager, I had this compact radio that was somehow amazing at finding CFLs.
At some point, it beautifully transmitted a sound best described as "fffFFFINK". No idea if that was a CFL PSU transmitting its last good bye or aliens.
they also make decent flyback drivers...
You can connect a flyback transformer to the driver and make a high voltage supply, im gonna make, its kind of like a ZVS driver ⚡
Halogen bulbs require a driver? 🤔
Well, the ones that run at 12 volts need a way to get that low voltage, and without an old-fashioned 50/60Hz transformer I guess that means a driver...
@@markiangooley yeah I later got to know that this is a Step down constant voltage SMPS regulator.
@@pravardhanus This is actually an unregulated SMPS, the output voltage is far from constant. Regulation requires more circuitry and would also prevent dimming.
Original ST application note for those interested:
www.st.com/resource/en/application_note/cd00003902-electronic-transformer-for-a-12v-halogen-lamp-stmicroelectronics.pdf
funny you should mention led lights clive, i was at a newly completed job the other day were some twit had fitted these transformers on led lights rather than drivers. needless to say the led's were dead. i can remember the old halogen transformers in the early 90's and they were solid heavy wire wound transformers better than this kak that they produce nowadays.
Funny? When does Clive not mention LED lights?
A fusible resistor. It’s a component which limits inrush current and acts as a fuse.
I remember bying one of these thinking it'll be able to drive 12V LED strip. Guess what!
You fried the LED strip.
@@simontay4851 It didn't even start!
I tried full bridge rectifier on the output, two LED strips in reverse-parallel, shunting the output with a low power 27V bulb, shunting with a resistor. Nothing!
LEDs started display Star Wars movies? 🌟
@@matijakukec4731 It was more like playing Doom3 on a lowest brightness with a monitor turned off.
@@777anarchist 😂😬😅
circuit looked really familiar, you think a smd version would be as loud?
Very likely, the noisiness of the circuit comes from how it operates, not from using through-hole technology.
@@Agent24Electronics my thinking was maybe the smaller components would have less of an effect, hopefully being better made, or made differently from their larger counterparts
Ah. It's already up.
Would it be safe to say that the quality control label applied over the ventilation holes does, in fact, control the quality?
You’re definitely onto something there :)
Nasty, but interesting too!
What a nasty circuit. Bzzzt. Bzzzt. Bzzzt. Yuk! Electronic version of the Buzz bomb jet engine!
I measured a 65 VS unit made by Ring. A solid looking unit. 20 watt halogen load. 12.2 V rms once a window suiting 48 kHz was found. This also captured a good looking square wave. The odd looking Forth bridge wave was seen. Ring say OF 0.99 !
Hi Clive, is there any way of getting into contact with you other than RUclips comments as I would like to send you a power supply I have for my iRobot Scooba, it’s an American 120v input and I mistakenly didn’t use a 240v step down transformer when plugging it in, lots of yellow capacitor urine everywhere. I was wondering if there would be anyway to step 240v down directly inside of the power supply to 120v and then put it back out onto the power supply’s main board.
Please am looking for an alternative to power halogen lamp inside microscope
Try connecting a copper coil in the output of the halogen driver and put a piece of iron in the coil i think it would cause the iron to heat up
Everything ok Clive? You seem to cough an awful lot. Sort of little coughs after each bit of speech.
I've been under the weather.
bigclivedotcom hope you get well soon! Try vocalzone lozenges to sooth your throat. Only thing I’ve found to have any effect