Mains operated LED lamp
Description.
This is a very simple and cost effective mains operated LED lamp which gives a very bright white light.Since no transformer is used, the circuit is very compact and light weight.The mains supply is given to the bridge rectifier via the parallel network formed between R1 and C1.The bridge rectifies the mains supply.The resistor R2 limits the current through the LEDs.The capacitor C2 acts as a filter.
Circuit diagram with Parts list.
Notes.
- The circuit can be assembled on a general purpose PCB.
- The bridge D1 can be made by using four 1N 4007 diodes.
- D2 to D13 can be bright white LEDs.
can u tell how much power will it dissipate
Thanks JOHN,
This is what i was looking for. can i use this method of AC to DC converting (With out transformer) for any of our needs. so what are the parts need to be change to get required Voltage + Current in DC.
Also pls adv what parts i have to change if i need to increase the amount of LEDs (Say 24 or 48).
Really Really good project & very use full.
Dears Mr.John,
Thank you very much for the circuit. You would have given the voltages at each point, which most of the circuit builders tend to overlook, considering that all people are of their potential. Many of your readers are aged more (me at 54), but lack the full electronic knowledge. Some years before, I have heard that LEDs drop a voltage of 3V. Can I use this phenomenon and put 100 LEDs in series and connect them to the 230V AC mains (i am from India)?
Hi Prasad,
First of all my electronic knowledge is very beginner level & so even i don’t know whether i’m right or wrong. Your point is correct, but then we need to consider the current that all 100 LED going to consume. Basically white LEDs are rated 20-25 mAmp. so we need to choose bridge rectifier according to that (at least 3amp + Voltage rating more than 230V)
But i can’t understand what are the numbers for R1 & C1 should be. R2 could omit as there are no left over voltage to resist. but C2 may still require & no idea about numbers.
So we need a help on this from a person who familiar with electronics to explain how this circuit is working. So beginners (Like me) can understand what should do to increase LEDs.
Please somebody help us on this………
Hi sathika If you want to use 100 LEDs, can connect two groups of 50 LEDs in series. Each LED requires 3 Volt @ 50mA (high bright LEDs available in India) Hence 150 Volt at (50 plus 50) 100mA. C1 should be 3mFD, increase R2 to 220 ohms 5 watt. I will be sending an article with proto type to “Circuits today” soon. the first proto type is in service at my home for the last 3 weeks in my pooja room (non stop working). I have kept it on reliability check. this will replace all my lights at home so that i/we can save lots of energy
Hi SEETHARMAN,
Thanks a lot for the help, I’m looking forward for your proto type circuit for main operated LED lamp. hope this is giving sufficient luminance to use out side as well as inside the house.
One thing i need to clarify (As still i’m a beginner) how will be the current consumption is limit to 100mA? as basically only 1 LED will run between 15-20mA (O/wise no much luminance)so 100 LEDs will consume 20mA x 100 = 2A, so the wattage??
Also i read some articles & all of those mentioned this will worth if we are getting 20-50mA max out of this. O/Wise this will not cheaper than using a Transformer. is it correct??
Pls clear this for me.
Hi Sathika as the LEDs are connected in series the same current will flow through all the LEDs in that chain, only the voltage will get multiplied. for 50 LEDs 50 X 3 150 Volts at 50mA. Say each LED consumes 50mA at 3 Volt. 3 x 0.05=0.15 watts. for 50 LEDs 50 X 0.15 = 7.5 Watts. In other words 150 Volt X 0.05 Amp = 7.5 Watts.. If all the LEDs are connected in parellel then it will be 3 Volt at 2.5Amps(0.05 X 50 LEDs) same 7.5 watts. with the capacitor in series due to power factor the consumption will be almost the same as per LEDs consumption.
Hi Seetharman,
Thanks a lot for the nice explanation. so all 100 LEDs will come close to the 15Watts. is it equal to the normal CFL 15W light’s luminance? Otherwise this is pointless.
Also what is the truth others saying about this Transformer less power supplies. i mean max current output that we can get almost less than 100mAmp. unless we change the C1 to a Very big & expensive AC type capacitor. is it correct??
Anyway i’m looking forward to your circuit diagram for the increased LED lights. appreciate if you can make a comment here also after you posted the article.
Dear Mr. Seetharaman,
I am Nikhil Goenka from Delhi. We have developed LED based bulbs and we are using the circuit that is mentioned above in our 35 LED, 30 LED, 15 LED a7 7 LED pcieces. But after use of 3-4 weeks, the luminance of led’s drops.
Can you please contact me if you can help us out in improving the circuit. If yes please mail me at nikhilgoenka@live.com
Dear Sri. Seetharaman,
Thank you very much for the circuit and for the explanations. Hope you have answered Mr.NikjilGoenka too, but it is not published. I too face the same problem. Of course, I dont make things in bulk, but for my own living room lighting.
Thank you, Sathika, for getting answers for most of the problems. Hope Guru like Seetharaman and Student like you – will teach the whole lot of people like us. thank you once again and one and all involved, specially to CIRCUITS-TODAY.
Hi Hari kindly go through the article appeared in Circuits today as Mains Operated LED circuit. each component used has a function, the value of them are chosen as per the operation limitation of capacitors LEDs etc.
This is a well tried one and all problems are totally ironed out. you may assemble and try few lights may be in your bath room, verandha, reading table lamp etc. This will get easily fitted into 11watts CFL lamp enclosure and gives a better brightness.
hi,
all of you im doing a small project on led lighting circuit. For this i need a ckt that provides 12volts/1amp dc power supply without using transformer. this ckt should be mains operated
Hi Ramakrishna 230 volt to 12 volt 1,2,5,10 amps power supplies are available in the market quite small in size may be Taiwanese or Chinese make they are quite good. I am using one “Hi Power” make 12 volts 50 watts halogen bulb supply for the last 5 years without any problem ( size 2″ X 1″ X 3/4″). Price cheaper than good quality 50VA transformers.
hello! i’m sp! i need less price,high brightning,low wattage led driver circuit.so what should be circuit arrangement and component specification and how these all things can purchase