This is great... Big Clive always says during teardowns of cheap equipment: "It's just a simple capacitive dropper"... thanks to your fuller explanation, I finally understand what that actually is.
5 лет назад+914
It would be interesting to see GreatScott and ElectroBOOM collab.... xD
"As you can see a switching power supply is too big for my tiny ATtiny85 project so I will make my own power supply from 3 ENORMOUS capacitors!" GreatScott's logic :D
He also put it in a rather big enclosure... Suming this all up: It doesn't make sense - only for educational purposes - but practically it saves zero space after all. Lmao
@@fusseldieb I think it is still true that these power supplies CAN be much smaller. From what I can tell, he was kind of just using parts he had, and he was also not trying to 'compactify' stuff, since spread out components are easier to see. I can definitely understand how this kind of power supply could be far smaller than the other, since you can pretty easily get very small capacitors that still have enough capacitance, but you can only get a transformer and some 10 other capacitors so small. Definitely though, the specific design should not be used for lightweight purposes XD.
2 года назад
For 12mA, a 330nF capacitor, which is a lot smaller, will be enough. And a 1uF capacitor definitely will be. He also connected the LED wrong, a capacitive dropper only works with a full bridge rectifier or 2 LEDs. The circuit he build was a single diode rectifier with a capacitor.
@@TheCarpenterUnion Yep, I think zak is saying there's a maximum reverse voltage the LED can take and you need to be aware of that so as not to destroy the LED.
I learned about capacitive dropper circuits when I tried to add a timer to a heater. The PCB outputs 5V for some IC's, and I thought I could supply my Arduino with that. It surely worked without a hitch. The problem occured when I also connected the Arduino to my PC, because I was tired of disconnecting, checking on the heater if it works correctly, reconnecting, patching the software, etc. The moment I connected it, my breaker tripped, all capacitors on the arduino popped, the 5V line was toasted, and all my USB3 ports on the motherboard were dead. Luckily enough, the motherboard survived. I'd definitely recommend that motherboard for the durability. Will look up the model if anyone is interested. After closer inspection, i found out that the ground had continuity with the live/neutral wire. From that time on, I always check the power supply and conductivity before attempting any modification on cheap chinese appliances
it's not the inrush current that kills your LED's it's the reverse voltage needed to be dropped by the LED's. Inrush does kill your LED's though but much slower than that.
Ha! I was going to say that too about the reverse voltage. But as far as inrush, I don't think there is any in this circuit. Great idea by @Sean Smith to fix the circuit.
2.2uF X2 class caps can be sourced cheap sometimes. I have made pretty much the same circuit as presented here quite a few times for several projects. The power can be a bit dirty (AC ripple) and is subject to RF interference. I remember having a CD4011 quad two input NAND gate configured as an SR latch operating off this capacitor power supply, and the latch would often false trigger. From memory the problem was solved with some hysteresis and further smoothing of the supply with some 104 caps. I exchanged the CD4011 with a CD4093 and used some 104 caps on the SR lines of the latch. ☆Great Scott☆ it worked! ... Think outside the □ and mix in some ♡ then use your ☆ for success... Gret video and thanx for sharing!
Thank you for going over capacitive droppers and their dangers. They're VERY useful in small circuits but need to be handled with care. Using insulating rubber gloves is also a smart move.
Great Scott: my group regularly builds supplies similar to this in the 60W range with a 98% efficiency. We have gone up to 500W for some applications. There should be a TVS on the front end and a MOV on the load side too.
This is a really good video! Editing and camerawork is clean and excellent. I like the diagrams you draw along with the explanations, they look really slick. And of course, the content is the best part; explained well and clear. Keep up the good work!
This was the tutorial topic I was looking for ages , on the whole YT there wasn't a single good enough video on this topic ; and you made this !! Thanks a lot Great Scott !
Hello Scott, I can recommend you "hi-link 5v" for powering your projects, it's super small, quite cheap and does it's work. Also it's enclosured. Of course it can be bought from our chinese friends :)
When I was a kid, I _shocked_ to find that capacitive dropper actually, well, shocks. Still the worst shock I've ever gotten though. Unfortunately, the simplicity of this power supply comes at a cost. Besides its poor power factor and unisolated output, being an unregulated power supply, it's sensitive to load current, input voltage and even input waveform changes. Yes, you see that correct, even when the input isn't a perfect sine like for example, a modified sine wave from those cheap inverters, it really mess up the output of the power supply since it was calculated for a perfect sine and certain voltage and current range. Talking about inverter, one pro tip: don't use capacitive dropper based devices with modified sine wave inverter. It will result in overcurrent on the output of the power supply and possibly destroy anything connected on the output.
AC the most painful belt I've had was 115v 400hz on control stuff. DC was 267v (measured it after it bit me before I swapped the board) inside a radar. Burned a small hole in the skin on the knuckle.
Isn't this what the zener diode is meant to help with? To avoid the output voltage going high enough (within reason) and protecting the circuit from overvoltage damage?
Clamping zener is optional and some capacitive dropper circuit don't have clamping zener, mostly on things like, for example, LED lights and any device with internal rechargeable lead acid battery like flyswatter or emergency lights. These things aren't that sensitive to output changes on normal circumstances (slight input transient, etc) but definitely not designed for waveform changes. If I'm not mistaken, it's not about the RMS value. In fact, modified sine wave inverters do have around 220V RMS, with slightly lower peak voltage than sine wave for compensation. I believe it's about the formula. Different waveform requires different calculation, just like how you calculate RMS voltage from peak voltage with different waveforms.
That was a really good presentation! I love the way you draw little graphs next to each stage of a circuit to illustrate what's happening at that point - that's a really good idea.
Love your clips .. I'm a 60yr old and have a passion to add electronics to my bucket list ...please make video clips for electronics for dummys like... myself. please
I've actually spent a lot of time messing with something similar in a circuit simulator and I had a lot more luck using an inductor as the reactance source rather than a capacitor. Putting a proper sized capacitor in parallel also greatly improves the power factor. That being said I also forwent the rectification and connected a pair of LED's with reversed bias directly in series with the reactor
@Great Scott - the first schematic and connections you showed almost certainly failed due to an LED's low reverse breakdown voltage typically WAY less than the PIV of mains. The simple inclusion of a reverse biased 1N4007 rectifier in parallel with the LED will solve that problem and a suitably specced inrush power resistor or better yet a suitable NTC in series with the input will solve (or massively reduce) the inrush current.
Hi Bob, did you mean a diode in series with the LED. This is how I used a 1n4005 diode in series with the LED to protect the LED from the high PIV that does kill the LED which was around 5 volts for the LED. However I was using g a resistor instead of a cap.
@@MegaVoltMeister no I didn't simply because with a capacitive dropper you need to allow the capacitor to both charge and discharge. With a resistive dropper you don't have that problem so EITHER will work, however the effective power dissipation in the resistor will increase (effectively double) if the rectifier is in parallel (full wave current through the resistor vs half wave). A resistor is fine with LOW AC volts, just as with DC volts, but the capacitive dropper is much more effective dissipation wise. Just beware the "bad" power factor.
but perhaps there is way to use cap and led circuit with mains AC , what will if i add diode parallel with led but opposite direction then led than that cap will enable to charge and #Discharge( reverse charge ) in both direction first via led then via diode so in such way led will survive from reverse cycle :) should be
8:26 don't we need to subtract that zener voltage (5.1v) from that 233volts AC voltage and then divide it with calculated reactance to get our current value.
the 5.1 volts across the zener is negligible compared to the 233 volt mains. Do the calculations with and without it and you'll find only a couple of percent difference. The tolerance in the capacitor value is likely to be far greater than a few percent, so you're never going to get exact values anyway. This is the case in most electronic circuits, where components with tolerances of 5% - 20% are regularly used and in most applications this doesn't matter as long as the components are generously rated. It would be like using Google Maps to calculate the length of a car journey, then adding on 6 feet to allow for the length of your drive.
Years ago, when I was young, I tried powering a DC motor with one of the capacitive dropper circuit which I found inside an LED lamp. A few minutes later, I was able to witness the power resistor being converted into a smoking light bulb.
0:59 He needs to power the project through the AC outlet of his surge protector, yet there's a USB indicator for charging just below that socket. You do you...
The tinkerning part is not isolated from mains power, thus landing this project in "High Voltage" land, the land where mistakes kill you. Yes, it is possible, but only for the very experienced.
The REAL reason why your LED kept blowing up was the missing full bridge rectifier. Only in the first half of your AC wave your circuit was a voltage dropper, in the second half your LED is driven backwards. And in backward direction an LED basically acts like an open circuit, which means the entire 230 Volts are on the LED, until it blows.
Could be either/or. Plugin in near the top of the mains sine wave the empty cap is like a short and you have 230V spike at the LED. The direction does not matter in that case. But yeah, connecting LEDs to more than 5V (typical) reverse voltage is a no-no (and completely ignored in the video).
This was very educational for me. You must have been reluctant about doing a video about working with mains. Thank you for taking a chance and sharing your findings.
That was such a simple explanation of a very complicated formula and setup. I really feel I have a much better understanding of capacitive dropers now and feel I can start to use and implement them, I have a little easier time in the states at 110V ...lol..
Hi GreatScott! I am from India. Great work bro👏! Keep it up👍. I watch almost all of your videos. I really appreciate the quality and content of your videos. Thank you for giving us such premium content.
Most Chinese/HK power supplies deliver less than or equal to half of their rated current. If you see what looks like the same unit, same voltage and different current capacities in advertisements, then surely the real current capability is LESS than half of the advertised current capability and the voltage will sag greatly. Go ahead and test them! So your cost savings is likely to cost more than triple, after burning out and needing to buy a proper power supply that meets your current needs. It would make a great video and perhaps people will use this video as a reference design for your own home-designed and built power supply. ;)
Capacitive dropping circuits are in common use in everyday items. However, they are usually either hardwired, or use a plug that cannot be reversed (grounded, or in the U.S., polarized). A good example is a ceiling fan with multiple speeds. In a typical build, at 120 volts, the slow speed is obtained by using a 4.3uF capacitor, the medium speed is obtained by using a 2.1uF capacitor, and the high speed is obtained by direct connection (no capacitor). No other electronic components are used nor are multiple winding taps to the motor.
I think your first attempt of cap + LED only needed a diode across the LED to work. That allows the cap to charge on the “negative” AC cycles. The LED will not be subject to high voltage but will blink at 50 Hz
Reminds me of my AC Fundamentals class. I still have nightmares from attempting to calculate values in Parallel RLC circuits. I still enjoyed watching your video and going over your calculations.
I am your big fan from INDIA., Odisha...please dont ever try to collab with any other youtuber.... As you are one alone enough to teach all of us.... May God bless you.....
Dear Scott: I have a suggestion: Instead of using a single capacitor in series with one side of the power line, why not put 2 capacitors of double capacitance value, one on each side of the power line? That way it doesn't matter which way the plug is plugged into the outlet. Also, if someone touches the output of the capacitor on the hot side, they will get a milder electric shock than they would if the circuit is made with just one capacitor, and some unlucky person plugs the plug in the outlet with the hot side being the non-capacitor side and touches the hot side. (Just a safety suggestion)
Watching this while wearing a "Full bridge rectifier" t-shirt from Electroboom and hearing Mehdi's voice when you pronounce it. Great video nonetheless, I like it that you did and explained the math for choosing the components.
You can simplify the circuit and remove 1 of those diodes. You do it by changing two of the diodes in the bridge to be zeners. This removed the need for the extra zener.
5:11 question here, since LED is diode, it shouldnt let current back, so maybe it was not burned but your capacitor blocked the current ? my expirement shows that if you connect half bridge after the capacitor led works fine.
Nice breakdown on capacitive droppers. My first introduction to them was a night light kit that I got online. It was only for 230 volt and, of course was very dim at 110 here in the US of A. So I played around and tried getting it working but ended up tossing the whole shebang in the bin. It did, however get me interested enough in this type of circuit to study and play around with them a bit. They can be useful in some instances, however I think I still prefer the old transformer with rectifier and filter method to obtain the DC voltages I need from the wall.
Back in the 90's I had to work with a company to design a custom SMPS for a project I was leading. What I found was that you needed LV power to run the SMPS control and could not use the outpt of the supply because the controller was needed to created it. Sort of a chicken before the egg problem. What I found was that the SMPS needed a small direct-mains supply to get everything going. These supplies usually can't generate much power; but, if you don't need much power they are very simple and may suffice. I am sure the IC I used is long gone. It is certainly long forgot. I did a quick Google and found NPC785A. It accepts up to 450V DC in (provided by a simple rectified DC) and can produce 5V out, 10mA. Note: If you go 3-prong you could rectify to ground and reduce some of the safety issues (but no all) - certainly doing anything directly with AC Mains can be lethal.
Can we all just appreciate how ghetto the "professional" circuit show at 5:54 is?! The power resistor is just soldered down with a big blob and the lead (which didn't even get trimmed) completely missed its through-hole. The film capacitor also ignored one of its pads and is bodged directly on to one of the mains lines, which themselves are soldered directly to SMD pads rather than proper through-hole connections. Not to mention all of the solder joints are cold welds and very poorly hand soldered (whats with all that residual solder on the green electrolytic cap?). Then it says RoHS towards the back as if they actually got certified. Best of the best right here...
can u add an inductor to the circuit instead of the inrush current resistor to take care of p.f and inrush current and the power loss caused by the inrush current resistor ?
Goddamn. I could have died cuz I literally opened up a ceiling fan circuit before I discovered your channel, and I literally harassed the dangerous circuit
My guess for the "secret" project: Home automation - A photodetector to monitor the light pulses from a smart meter and transmit the results over radio to a base station. Well, that's what I want to do, and was planning on using one of those SMPS modules, but this method could be a viable alternative if I can get the power requirements low enough.
Check always if capacitors are properly discharged. Also consider using an isolation transformer about 6VA for avoid single contact shocks , (but defeats eath) and less energy to blow up circuits
Great Scott : uses a mains voltage with a warning on the start
ElectroBOOM: holds 5k volts and no warnings
@@jkobain It still does hurt man^^
Because He is Mehdi Saghdar
So you can see what a capacitive dropper can't do😁😁😁
220v vs 110v
Because this fine Gentleman isn't stupid
Big difference between Greatscott and ElectroBoom
GreatScott: gives warning about 230V
ElectroBoom: Touches 2 Kv Transformer and just yelling around
rubber hand vs. hair hand :D
kV*
because in Iran human life is valueless
First you go home and touch 230 VAC then talk to GreatScott.
the warning is included within the show
This is great... Big Clive always says during teardowns of cheap equipment: "It's just a simple capacitive dropper"... thanks to your fuller explanation, I finally understand what that actually is.
It would be interesting to see GreatScott and ElectroBOOM collab.... xD
Tell mehdi to tour Germany. He went to Japan lately so it would not be unreasonable to ask him to visit Germany...
@@sortsvane Good thinking :D
Greatscott : uses rubber gloves
Mehdi : sits on nichrome wire to roast his ass
how to blow up everything the most efficiant way
Ask him to sit on it..
"As you can see a switching power supply is too big for my tiny ATtiny85 project so I will make my own power supply from 3 ENORMOUS capacitors!"
GreatScott's logic :D
He also put it in a rather big enclosure... Suming this all up: It doesn't make sense - only for educational purposes - but practically it saves zero space after all. Lmao
@@fusseldieb I think it is still true that these power supplies CAN be much smaller. From what I can tell, he was kind of just using parts he had, and he was also not trying to 'compactify' stuff, since spread out components are easier to see. I can definitely understand how this kind of power supply could be far smaller than the other, since you can pretty easily get very small capacitors that still have enough capacitance, but you can only get a transformer and some 10 other capacitors so small.
Definitely though, the specific design should not be used for lightweight purposes XD.
For 12mA, a 330nF capacitor, which is a lot smaller, will be enough. And a 1uF capacitor definitely will be. He also connected the LED wrong, a capacitive dropper only works with a full bridge rectifier or 2 LEDs. The circuit he build was a single diode rectifier with a capacitor.
I believe you pronounced "Full Bridge Rectifier" wrong.
It's supposed to be pronounced "FUUL BRIDGE REKTIFIAH", preferably with some kind of reverb.
فبقي
漢字
In Canukistan it's called a rectumfryer.
@@carpespasm In Germany it's a GLEICHRICHTER.
decay BRÜCKENGLEICHRICHTER
I've watched so many of bigclive's videos that I can actually understand this video lol
Clive squad 🖖🏽
Yea!!
+1
Woot
It took me this video to get bigclives video :)
When i first saw such a compact power supply in my home door bell, I was fascinated. Thanks for explaining the principles of the circuit.
@@jeffsadowski No. Modern mobile chargers are SMPS. They don't rely on capacitive reactance to drop out mains voltage.
@@jeffsadowski sure, if you like charging your 3,000mah battery with just 10ma /s
When you put the LED on main power, you need to take on concideration the reverse voltage on the LED with AC voltage.
It's a diode.
@@TheCarpenterUnion Yep, I think zak is saying there's a maximum reverse voltage the LED can take and you need to be aware of that so as not to destroy the LED.
@@TheCarpenterUnion Usually LED's have a maximum reverse voltage of 5V, anything more and you destroy the diode.
7:19 english subtitles are the best
Electroboom confirmed on subtitles
Agreeeeeeeeee lol
True
"jlcpcb sponsored this video" proceeds to create project just connecting pin to pin without using a single pcb...
Hush you.
because uses less WATs
To be fair, this garbage circuit doesn't deserve a pcb.
@@elijahvivio1996 it's a pretty useful garbage circuit tho
hahaha
soldering in mid air is a necessary skill. xD
I learned about capacitive dropper circuits when I tried to add a timer to a heater. The PCB outputs 5V for some IC's, and I thought I could supply my Arduino with that. It surely worked without a hitch. The problem occured when I also connected the Arduino to my PC, because I was tired of disconnecting, checking on the heater if it works correctly, reconnecting, patching the software, etc. The moment I connected it, my breaker tripped, all capacitors on the arduino popped, the 5V line was toasted, and all my USB3 ports on the motherboard were dead. Luckily enough, the motherboard survived. I'd definitely recommend that motherboard for the durability. Will look up the model if anyone is interested. After closer inspection, i found out that the ground had continuity with the live/neutral wire. From that time on, I always check the power supply and conductivity before attempting any modification on cheap chinese appliances
5:53 FULL BRIDGE RECTIFIER
oh wrong Channel
FOOUUHHL BRIDGHZG REKHKHHTIFAAIEERRRR
do you know what is GreatScott channel ? 😆
BEAR HANDS 11:18
@@norman7535 BEAR HANDS... BEAR HANDS... WHAT'S UP WITH BEARS IN THIS LANGUAGE?! I FEEL SO BEARLY TODAY... BEEAR!
Sechspuls-Brückenschaltung or even fuller rectifier
world philosophy can't use electronic technology without full bridgeeeee rectifierrrrrr @electroboom & @greatscott 2020 😂❤️🇮🇷
it's not the inrush current that kills your LED's it's the reverse voltage needed to be dropped by the LED's. Inrush does kill your LED's though but much slower than that.
To add to this, you can resolve the reverse current problem by adding another diode across the LED in the opposite direction.
@@rupert274 Wouldn't you have a bigger inrush current problem?
Why much slower? There was nothing limiting it
Ha! I was going to say that too about the reverse voltage. But as far as inrush, I don't think there is any in this circuit. Great idea by @Sean Smith to fix the circuit.
what i dont understand is why it worked with the resistor
2.2uF X2 class caps can be sourced cheap sometimes. I have made pretty much the same circuit as presented here quite a few times for several projects.
The power can be a bit dirty (AC ripple) and is subject to RF interference. I remember having a CD4011 quad two input NAND gate configured as an SR latch operating off this capacitor power supply, and the latch would often false trigger. From memory the problem was solved with some hysteresis and further smoothing of the supply with some 104 caps. I exchanged the CD4011 with a CD4093 and used some 104 caps on the SR lines of the latch. ☆Great Scott☆ it worked! ...
Think outside the □ and mix in some ♡ then use your ☆ for success...
Gret video and thanx for sharing!
GreatScoot: this can kill you
ElectroBOOM: hold my beer
*SeAt WaRmEr*
Thank you for going over capacitive droppers and their dangers. They're VERY useful in small circuits but need to be handled with care. Using insulating rubber gloves is also a smart move.
Great Scott: my group regularly builds supplies similar to this in the 60W range with a 98% efficiency. We have gone up to 500W for some applications. There should be a TVS on the front end and a MOV on the load side too.
Man your writing and symbol drawing is perfect
Great Scott: Advertises JLCPCB.
Also Great Scott: Builds dangerous circuit without any insulation hoping gravity won't burn his house down.
This is a really good video! Editing and camerawork is clean and excellent. I like the diagrams you draw along with the explanations, they look really slick. And of course, the content is the best part; explained well and clear. Keep up the good work!
I learned how to make capacitive droppers from Big Clive. They're great for making my own LED lightbulbs.
This was the tutorial topic I was looking for ages , on the whole YT there wasn't a single good enough video on this topic ; and you made this !! Thanks a lot Great Scott !
Hello Scott,
I can recommend you "hi-link 5v" for powering your projects, it's super small, quite cheap and does it's work. Also it's enclosured. Of course it can be bought from our chinese friends :)
I love how you explain everything and how precise and easy to read 6our schematics are!
0:29 the last time I try to sold an energized component, he blowup in my face... :D
Solder*
6:07
Electroboom needs that for all the times he plugs something in and it explodes in his face.
When I was a kid, I _shocked_ to find that capacitive dropper actually, well, shocks. Still the worst shock I've ever gotten though.
Unfortunately, the simplicity of this power supply comes at a cost. Besides its poor power factor and unisolated output, being an unregulated power supply, it's sensitive to load current, input voltage and even input waveform changes. Yes, you see that correct, even when the input isn't a perfect sine like for example, a modified sine wave from those cheap inverters, it really mess up the output of the power supply since it was calculated for a perfect sine and certain voltage and current range. Talking about inverter, one pro tip: don't use capacitive dropper based devices with modified sine wave inverter. It will result in overcurrent on the output of the power supply and possibly destroy anything connected on the output.
I saw this circuit it in every cheap rechargable lead acid emergency lights.. and shocked myself many times while opened
AC the most painful belt I've had was 115v 400hz on control stuff.
DC was 267v (measured it after it bit me before I swapped the board) inside a radar. Burned a small hole in the skin on the knuckle.
Isn't this what the zener diode is meant to help with? To avoid the output voltage going high enough (within reason) and protecting the circuit from overvoltage damage?
Is that because it's not the same RMS value?
Clamping zener is optional and some capacitive dropper circuit don't have clamping zener, mostly on things like, for example, LED lights and any device with internal rechargeable lead acid battery like flyswatter or emergency lights. These things aren't that sensitive to output changes on normal circumstances (slight input transient, etc) but definitely not designed for waveform changes.
If I'm not mistaken, it's not about the RMS value. In fact, modified sine wave inverters do have around 220V RMS, with slightly lower peak voltage than sine wave for compensation. I believe it's about the formula. Different waveform requires different calculation, just like how you calculate RMS voltage from peak voltage with different waveforms.
That was a really good presentation!
I love the way you draw little graphs next to each stage of a circuit to illustrate what's happening at that point - that's a really good idea.
Where is the video of this week?!!! I am going to cry 😥
Love your clips ..
I'm a 60yr old and have a passion to add electronics to my bucket list ...please make video clips for electronics for dummys like...
myself.
please
10:47 note: should read "inside a closed, non-conductive housing". I would even be tempted to goop the whole circuit
If the housing is grounded the breaker will trip if there is a short.
I've actually spent a lot of time messing with something similar in a circuit simulator and I had a lot more luck using an inductor as the reactance source rather than a capacitor. Putting a proper sized capacitor in parallel also greatly improves the power factor. That being said I also forwent the rectification and connected a pair of LED's with reversed bias directly in series with the reactor
Dangerous, you said? I'm definitely making this one.
OMG TheSmkngun, wear a face shield 😳
I usually don't understand your video (I'm a beginner I did not study it) but I guess I understood nearly everything in this one! Thanks!
@Great Scott - the first schematic and connections you showed almost certainly failed due to an LED's low reverse breakdown voltage typically WAY less than the PIV of mains.
The simple inclusion of a reverse biased 1N4007 rectifier in parallel with the LED will solve that problem and a suitably specced inrush power resistor or better yet a suitable NTC in series with the input will solve (or massively reduce) the inrush current.
Hi Bob, did you mean a diode in series with the LED. This is how I used a 1n4005 diode in series with the LED to protect the LED from the high PIV that does kill the LED which was around 5 volts for the LED. However I was using g a resistor instead of a cap.
@@MegaVoltMeister no I didn't simply because with a capacitive dropper you need to allow the capacitor to both charge and discharge. With a resistive dropper you don't have that problem so EITHER will work, however the effective power dissipation in the resistor will increase (effectively double) if the rectifier is in parallel (full wave current through the resistor vs half wave). A resistor is fine with LOW AC volts, just as with DC volts, but the capacitive dropper is much more effective dissipation wise. Just beware the "bad" power factor.
yes there should be diode to block reverse current from AC second cycle or rev voltage .
but this is case for rasistor
but perhaps there is way to use cap and led circuit with mains AC , what will if i add diode parallel with led but opposite direction then led than that cap will enable to charge and #Discharge( reverse charge ) in both direction first via led then via diode so in such way led will survive from reverse cycle :) should be
Exhausted my today's internet, totally fucked up, first thing to do to watch your video at 00:00 (GMT+5:30) When my datapack renews. 🙄😁😁😂
8:26 don't we need to subtract that zener voltage (5.1v) from that 233volts AC voltage and then divide it with calculated reactance to get our current value.
the 5.1 volts across the zener is negligible compared to the 233 volt mains. Do the calculations with and without it and you'll find only a couple of percent difference. The tolerance in the capacitor value is likely to be far greater than a few percent, so you're never going to get exact values anyway. This is the case in most electronic circuits, where components with tolerances of 5% - 20% are regularly used and in most applications this doesn't matter as long as the components are generously rated.
It would be like using Google Maps to calculate the length of a car journey, then adding on 6 feet to allow for the length of your drive.
What a perfect timing! I was looking for a tutorial on this topic
Greatscott:This is very dangerous
ElectroBOOM:hold my wire
Years ago, when I was young, I tried powering a DC motor with one of the capacitive dropper circuit which I found inside an LED lamp. A few minutes later, I was able to witness the power resistor being converted into a smoking light bulb.
hi sir i like your videos im from india im also a youtuber
love from india
@Dio Brando pewrandi
bestest ever video on capacitive dropper circuit.
0:59 He needs to power the project through the AC outlet of his surge protector, yet there's a USB indicator for charging just below that socket. You do you...
His hand writing is so perfect.
6:01
but why? these circuits meant to be as cheap as possible while being very operational and optimal. whats the problem?
The risk of electric shock+fire.
The tinkerning part is not isolated from mains power, thus landing this project in "High Voltage" land, the land where mistakes kill you. Yes, it is possible, but only for the very experienced.
A big love from India to great scott
The REAL reason why your LED kept blowing up was the missing full bridge rectifier. Only in the first half of your AC wave your circuit was a voltage dropper, in the second half your LED is driven backwards. And in backward direction an LED basically acts like an open circuit, which means the entire 230 Volts are on the LED, until it blows.
Could be either/or. Plugin in near the top of the mains sine wave the empty cap is like a short and you have 230V spike at the LED. The direction does not matter in that case. But yeah, connecting LEDs to more than 5V (typical) reverse voltage is a no-no (and completely ignored in the video).
GreatScott:
Electroboom: BOOOM!! 💥
Could you please make a video on how to build a SMPS and the concepts it requires.
Maybe one day.....not sure.
You are very good teacher. You method of explaination is very intuitive.
I always wait for your awesome video.
Thanks
Make a video on vacuum fluorescent displays!
This was very educational for me. You must have been reluctant about doing a video about working with mains. Thank you for taking a chance and sharing your findings.
Next time please pronounce *FHUUL BRIADGE RHECKTHIFIA* right with some reverb
I am researching to build one, and you come to my rescue.
Beter end the video with: "Stay alive, and we may see you next time!"
You made me laugh 😀
Thanks for walking through this, it helped quite a bit.
Dangerous and it doesn’t supply much power on the output?
Wow, count me in!
That was such a simple explanation of a very complicated formula and setup. I really feel I have a much better understanding of capacitive dropers now and feel I can start to use and implement them, I have a little easier time in the states at 110V ...lol..
*FULL BRIDGE RECTIFIER*
why i hear Mehdi voice
Some may hear it as a Full Bridge Rektumfryer.. hee-hee
Hi GreatScott! I am from India.
Great work bro👏! Keep it up👍.
I watch almost all of your videos. I really appreciate the quality and content of your videos.
Thank you for giving us such premium content.
the scariest thing about this is his unique wire-tangle prototyping method... what's wrong with a breadboard?
I have exactly the same issue, and this is why I ordered from China the HLK-PM01 switched mini power supply module, around 3 EUR
Most Chinese/HK power supplies deliver less than or equal to half of their rated current. If you see what looks like the same unit, same voltage and different current capacities in advertisements, then surely the real current capability is LESS than half of the advertised current capability and the voltage will sag greatly. Go ahead and test them! So your cost savings is likely to cost more than triple, after burning out and needing to buy a proper power supply that meets your current needs. It would make a great video and perhaps people will use this video as a reference design for your own home-designed and built power supply. ;)
FULL BRIDGE RECTIFIER
*ElectroBOOM wants to know your location*
He knows him, in germany
Capacitive dropping circuits are in common use in everyday items. However, they are usually either hardwired, or use a plug that cannot be reversed (grounded, or in the U.S., polarized). A good example is a ceiling fan with multiple speeds. In a typical build, at 120 volts, the slow speed is obtained by using a 4.3uF capacitor, the medium speed is obtained by using a 2.1uF capacitor, and the high speed is obtained by direct connection (no capacitor). No other electronic components are used nor are multiple winding taps to the motor.
I think your first attempt of cap + LED only needed a diode across the LED to work. That allows the cap to charge on the “negative” AC cycles.
The LED will not be subject to high voltage but will blink at 50 Hz
This is correct, he got 600v reverse voltage on the LED in the negative cycle.
Superb video, finally understand capacitive droppers!
You taught me more things than my electronic school... Thanks
This is the only circuit of yours that I have clearly understood
For most of my circuits/projects that require mains to
the great coincidence that i started using this type of Power Supply lately by doing exactly the same thing you did lol
Reminds me of my AC Fundamentals class. I still have nightmares from attempting to calculate values in Parallel RLC circuits. I still enjoyed watching your video and going over your calculations.
I am your big fan from INDIA., Odisha...please dont ever try to collab with any other youtuber.... As you are one alone enough to teach all of us.... May God bless you.....
Love your schematics and calculations.
This kind of supply is used in many small devices, like Teckin SP22 smart plug. Very interesting and dangerous. Congrats.
Dear Scott: I have a suggestion: Instead of using a single capacitor in series with one side of the power line, why not put 2 capacitors of double capacitance value, one on each side of the power line? That way it doesn't matter which way the plug is plugged into the outlet. Also, if someone touches the output of the capacitor on the hot side, they will get a milder electric shock than they would if the circuit is made with just one capacitor, and some unlucky person plugs the plug in the outlet with the hot side being the non-capacitor side and touches the hot side. (Just a safety suggestion)
Watching this while wearing a "Full bridge rectifier" t-shirt from Electroboom and hearing Mehdi's voice when you pronounce it. Great video nonetheless, I like it that you did and explained the math for choosing the components.
Outstandingly informative and concise.
One can use inductance coil, to limit the current during capacitor charging. That could save your LED when you plug in the socket
You can simplify the circuit and remove 1 of those diodes. You do it by changing two of the diodes in the bridge to be zeners. This removed the need for the extra zener.
We need to get Scott, Mehdi and Kreosan together. Boom!
5:11 question here, since LED is diode, it shouldnt let current back, so maybe it was not burned but your capacitor blocked the current ? my expirement shows that if you connect half bridge after the capacitor led works fine.
Nice breakdown on capacitive droppers. My first introduction to them was a night light kit that I got online. It was only for 230 volt and, of course was very dim at 110 here in the US of A. So I played around and tried getting it working but ended up tossing the whole shebang in the bin. It did, however get me interested enough in this type of circuit to study and play around with them a bit. They can be useful in some instances, however I think I still prefer the old transformer with rectifier and filter method to obtain the DC voltages I need from the wall.
Back in the 90's I had to work with a company to design a custom SMPS for a project I was leading. What I found was that you needed LV power to run the SMPS control and could not use the outpt of the supply because the controller was needed to created it. Sort of a chicken before the egg problem. What I found was that the SMPS needed a small direct-mains supply to get everything going. These supplies usually can't generate much power; but, if you don't need much power they are very simple and may suffice. I am sure the IC I used is long gone. It is certainly long forgot. I did a quick Google and found NPC785A. It accepts up to 450V DC in (provided by a simple rectified DC) and can produce 5V out, 10mA. Note: If you go 3-prong you could rectify to ground and reduce some of the safety issues (but no all) - certainly doing anything directly with AC Mains can be lethal.
Can we all just appreciate how ghetto the "professional" circuit show at 5:54 is?! The power resistor is just soldered down with a big blob and the lead (which didn't even get trimmed) completely missed its through-hole. The film capacitor also ignored one of its pads and is bodged directly on to one of the mains lines, which themselves are soldered directly to SMD pads rather than proper through-hole connections. Not to mention all of the solder joints are cold welds and very poorly hand soldered (whats with all that residual solder on the green electrolytic cap?). Then it says RoHS towards the back as if they actually got certified. Best of the best right here...
Pretty nice job! And really interesting circuit! 😃
Great Scott you are great as name , many doubt clear after seen this video
can u add an inductor to the circuit instead of the inrush current resistor to take care of p.f and inrush current and the power loss caused by the inrush current resistor ?
Goddamn. I could have died cuz I literally opened up a ceiling fan circuit before I discovered your channel, and I literally harassed the dangerous circuit
Exactly what I was looking for!
You are great whenever i am thinking to experiment on any topic you uploads a video on it
Thanks for the explanation of the rubber gloves
Very nice video. It would be interesting to see the behaviour of the circuit under different loads.
Bigclive has many videos about this kind of power suply. You can't go wrong watching his videos.
My guess for the "secret" project: Home automation - A photodetector to monitor the light pulses from a smart meter and transmit the results over radio to a base station.
Well, that's what I want to do, and was planning on using one of those SMPS modules, but this method could be a viable alternative if I can get the power requirements low enough.
Check always if capacitors are properly discharged. Also consider using an isolation transformer about 6VA for avoid single contact shocks , (but defeats eath) and less energy to blow up circuits
Fooooooooooool Bridge rectifier *makes the super man thingy
BINGO!! just what i needed!!!!!!!
For lighting up few led we don't need complex components only resistors of appropriate value is sufficient. We see in indicators.