Mains operated LED lamp

CircuitsToday has introduced an online bookstore where 4 books on basic electronics are reviewed in detail. These books are written by renowned authors like Forrest M Mims, and other famous personnels. Please go through the reviews and buy them from here:- 4 GREAT BOOKS TO LEARN BASIC ELECTRONICS

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.

mains-operated-led-lamp

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.
Custom Search

Leave a Reply

93 Responses to “Mains operated LED lamp”

  • Jithin says:

    hi Seetharam sir
    I would like to make a bright led lamp for household use which works as normal light when supply main is available and also as an emergency lamp when supply is turned off.
    I have tried some circuits but lacking practical kowledge.I am planning to start a small scale production with this idea for household lighting so please help me out.

    • seetharaman says:

      Use 24 to 36 High bright (similar to 50-50 6 pin SMD LEDs capable of operating at 60mA current) Use 12 volt 7AH battery with charger to operate it. Use MOSFET for auto change over to operate 4LEDs in series. So the current is limited to 300 to 500mA. It will allow the emergency operation for a minimum of 14 hrs non stop with a fully charged battery.

  • Lusa says:

    Hi
    Kindly let me know how(method)TO GET THE RIGHT value for the poly capacitor labeled CL21/684J/250V in micro farads, again another one written L105J/250V

  • Lusa says:

    Hi
    Kindly let me get the formula for calculating the values for R1 and C1 for a DC output of 12V across C2, OR the formula for calculating the values of R1 and C1 to get a DC output of X Value across C2 point.

    Thanks

  • pratiksha says:

    What is the exact design to build mast led light with same intensity of hps light….?
    how much led will require and its specification….

  • ravi says:

    dear sir ,
    in this ckt we r using only 13 led. i want use 80-100 led in my projects .what changes will be needed? .help me sir .

  • Cameron says:

    Hi
    Just wondering if you had any ideas on a circuit to run 50watt Leds from 240v AC I was thinking of running as many 50watt modules in series to add up to the voltage that would be produced after filtering 240volt AC. About 9 modules all up on a large fan cooled heatsink. Yes it would be very bright.
    Cheers
    Cameron

  • aditya says:

    through this same circuit can i get 40 v dc please tell the changes to be made

  • Lakmal devinda says:

    Sir,can we build a 16w led lamp using 16*1w 3.6v power leds from this power supply model?If we can,what are the changes.Plz exaplain sir

  • bilal says:

    hello
    how much leds (maximum) could be connected with this circuit?
    without loosing brightness.

  • Arvindan says:

    Hi
    How to choose capacitor C1 & resistor R1 values. It is any formula for it? I want to drive 100-120 high brightness LED from 240-250 V 50 Hz AC. What changes will be required?

  • Michael says:

    I are trying to build a flashing led sign with 3 stage flashing and 1 color on all the time . The on full time color has 107 red superbright 5 mm domed leds .app.3.5 ma . The flashing colors are blue 32 5 mm superbright blue leds , green 5 mm superbright leds qty 10 , and yellow superbright 5mm leds qty 18 .We have tried all the available circuits on the net for 220 -250 volts 50 hz but find we have a massive power drop which does not light up sufficiently or very dimly . Furthermore , I am trying to create the flashing effect with a 555 ic . The sign is supposed to flash green , yellow , blue repeatedly while the red leds stay on and do not flash . Is there anyone on this site with the knowledge to assist me with a viable circuit either in parallel or series which would work for this application or maybe a challenge for the very capable experts on this site . Your assistance would be most appreciated .

  • Seetharaman says:

    Hi Mahajan The reactance of the capacitance (AC resistance) is used as series, instead of a resistance in series. using the formula
    F = 1 ÷ {2π (R X C)} where F is the frequency in Hz, R is resistance in ohms and C is capacitance in Farades. Since the current lag voltage by 90 deg across capacitor the power dissipated is Zero, hence no loss across like resistance. The high value resistance across the capacitor is used to discharge it when the supply is switched off.

  • Sourav mahajan says:

    How the parallel combination of a capacitor and a resistor can act as a step down transformer ?…..definitely we have to step down the mains voltage from 230V to something much lower say 10v – 20v for leds to operate and also much less current..what is the theory behind using this parallel combination of cap and resistor…kindly explain.

  • Seetharaman says:

    Hi Adesh May be the 1uF is defective it can never blow in this circuit. You may add a 56 ohms 2watt in series with the mains lead which is directly connected to Bridge rectifier, which may limit the incomming surge current.

  • Hi, Dear Mr.Seetharaman
    in my house most of the time voltage range 250-260 V

  • Hi, Dear Mr.Seetharaman
    my circuit was working fine from last 4 days. I was using it 4 to 5 hour a day, but today LED’s starts dimming then closed, my 1uF 400 V polyester capacitor was blone, kindly tell me the resion of it and tell me what to do?

  • in my house most of the time voltage range 250-260 V

  • my circuit was working fine from last 4 days. I was using it 4 to 5 hour a day, but today LED’s starts dimming then closed, my 1uF 400 V polyester capacitor was blone, kindly tell me the resion of it and tell me what to do?

  • Remen Jose says:

    Hi! i would like to ask if i can used different colors of LED in this circuit..thanks…

  • Dear Mr.Seetharaman. If I use highbrite led of 100mA current I shall have to change wattage of the resistance.What will be the value of the resistance?Thanks

    • Seetharaman says:

      Hi Mukherjee without any modifications you can disconnect D2 to D13 and just use 5 LEDs of 100mA in series. This circuit is capable of max 100mA only.

  • Shashi Suman says:

    Hello setharaman sir…my retailer said me that 1000uF is better than 680uF 50v …so should i use it or something else….if ur ans is 2nd then what should i do

  • Seetharaman says:

    Hi Kosala disconnect from mains physically check the components, if all are looking alright, feed 6 volts DC across C2 if all the LEDs are glowing alright, either the capacitor C1 is defective or 1N4007 are defective (this is normal with some batch of diodes available in the market may be 1N4001 printed as 1N4007 by greedy retailers, i faced the same problem, when I bought these diodes from one particular shop, now I have changed my supplier)

  • kosala says:

    please help me………..I build up this circuit…it worked properly…after a few(about 14 days) days,the LED didn’t work…plese let me know the reason why it happened so………

  • Seetharaman says:

    Hi Bikash C1 is polyester with 400volt DC rating (250volt AC capacitor also can be used and C2 is used in DC circuit with a rating of 50volt DC.

  • bikash says:

    heloo sir ,is C1 and C2 ac or dc?

  • Prasad.M says:

    Emergency light: 9W CFL bulb, 6V 4.5mA Battery.

    If i am replacing 9W CFL with LEDS, how many LEDS should be used and which LED to be used?

    Any necessary changes to be done for LED ckt.
    Previous replay i didnt get it. Plz specify clearly.

  • Seetharaman says:

    Hi Prasad use simple Emergency light circuit with a by pass switch to use the light as normal LED light. The circuit will work for 8hrs non stop with fully charged battery. For power LEDs the requirement is > 500mA it is better to use switched mode power supplies.
    Hi Vonoth you can use standard 3.2 volt 25mA LEDs in Mains operated LED lamp project with 1uF reduced to 0.68uF.

  • Prasad.M says:

    Emergency light: 9W CFL bulb, 6V 4.5mA Battery.

    I need to replace 9W CFL with LEDS. So how many LEDS should be used and which LED to be used. What might be its Life span and stand by time.

    Specification of Emergency Light: Normal design which you get in market

  • Prasad.M says:

    Can this Circuit be implemented with Power LEDs.
    What is the life span of your designed circuit.
    What all the changes to be done in the circuit, if i am using 25 nos Ultra bright LEDS.

  • VINOTH.S says:

    Sir, i want to connect 50 led’s in series connection. is it posssible with four IN4007 diodes,474k 250v capacitor,and a resistor of 2.2Mohms.pls tell the circuit design.

  • virender says:

    Hi all, can anyone please tell me how to make 50/100 watt with 1000 Leds (White) using transformerless power supply. Any reply shall be highly appreciated. Thanx in advance! Please mail me to “vrndrsngh85@gmail.com”

  • shobha kumari says:

    battery voltage state indicator.

  • arun says:

    Dear Seetharaman,
    Hello!!
    Having just come across your site i find in your posts a wealth of information.You are doing a great job.Hats off to you.
    As a CSR project for the BOP we would like to produce 5W/8W AC LED bulbs using 20mA, 3.2V smd LED’or 50mA, 3.2v smd Led’s.Is it possible to make these bulbs with your circuit to operate directly on 220V AC and without using constant current drivers.If yes can you suggest suitable circuits?
    What will be the effect of such a circuit arrangement on the Power factor, THD and CRI.?
    Is your circuit able to take care of voltage fluctuation which is a sad reality in India.
    How is the current kept within the safe operating limit of the LED’s.
    Your guidance will be highly appreciated.
    Thanks
    Arun
    bestbrand@gmail.com

  • arun says:

    What will be the THD(Total Harmonic distortion) and PF
    Can this work for a high power LED say upto 8W having a string
    LED’s in a configuration of 40 x3

  • Seetharaman says:

    Hi Bhuvnesh Using 50LEDs in parallel will ammount to 1.25amps requirement you have to raise the capacitor C1 value to 25uF 400volts AC. will be a costly proposition, instead you connect you LEDs in series and use in the following circuit
    http://www.circuitstoday.com/mains-operated-led-circuit reduce 1uF 400volts to 0.47uF 400volts.

  • bhuvnesh kumar says:

    dear sir thanks for this great ckt.
    sir i want to connect 50 LEDs. then what will be
    the value of resistance and capacitors in the ckts.

  • Feranando says:

    podrian ser amables de publicar la fotografia de la placa PCB,para asi poder armar el circuito ,ya que no entiendo mucho de electronica soy autodidacta,o mas bien dicho grafico de antemno muchas gracias.

  • seetharaman says:

    Hi Rohith it is 0.5watts minimum

  • Rohith says:

    Plz… Tell me, which wattage resister (R1) is to be used for this circuit… ?

  • seetharaman says:

    Hi Suketu 20LEDs of say 3.2volt @ 25mA in parallel 3.2 volt at 500mA. Look for an SMPS for 3.2volt at 600mA or greater. this will fit your requirement.
    Hi Deepak you can use a multi vibrator using HV transistors and connect your chain to their collectors.

  • Suketu says:

    Hi All

    I am required to drive 20 White LED’s – all connected in parallel from 230 V AC without using a Xmer. Can any one guide me how can i implement this..

    Suketu

  • deepak says:

    Hello sir, i want to make mains operated 2 chains blinking led circuit with 25 leds in each chain and 2 chains should flashes alternately. Can you suggest me the circuit?
    plz reply!

  • NemO says:

    Hi Seetharman,

    Nice thread here! Just want to ask a noob question, from your circuit diagram above, what is the wattage rating of R1, is it 1/4 watt or 1/2 watt? I’m planning to build a simple LED light for my small aquarium. Thanks for your assistance.

    Thanks,
    NemO

  • Seetharaman says:

    Hi Sharuk you have to use 1uF 400 volt polyester capacitor only as the supply is AC. the electrolytic capacitor will a dead short for AC this is the reason why every thing has blown. you are lucky that you are not hurt.
    Hi Kamal give full specifications of your LED

  • Sharuk says:

    Hi, I created this circuit and all my LEDs burned, also the 1uf capacitor. What should be the case. I used 1uf electrotype capacitor.

    Thanks,
    Sharuk.

  • Seetharaman says:

    Hi Isuru 105k is 1uF can be used. for 680- you can use 1no 470 and 1no 220uF 50V in parallel. 100k is good enough.
    Hi kamal 60watt LED?

  • Kamal says:

    I want make a 60 w led lamp.
    Pls help me

  • isuru kalhara says:

    is it ok to use 105k 400v thin film capaciter insteed of 5uf 400v poly capaciter? And also i cant find 640uf 50v capaciter. So can you suggest me a way to create 680uf 50v capaciter using some other capaciters? Please help me. And is it ok to use 10k + 100k resisters for 110k?

  • Seetharaman says:

    Hi Arie you must be using standard 25mA LEDs. if so reduce 1uF capacitor to 0.47uF to limit the current to the tsafe limits of the LEDs. In my house it has been under service for the last six months (13 LEDs with 0.47uF)it is still maintaining 210 Lux at 1 meter.

  • arie says:

    The series was I created, with 20, 25, 30 led me chain series,there were 22 series . One room I can place 3 series and I use it in three rooms added to the two sets of street lighting. I turned on the light let it for 12 hours a day, at the time of sunset to sunrise again. Led the first month began to dim, entering the second month …. in the second week, seven-circuit die. (seven of this series I replace with a new series), entered the day 50 … 6 fruit series of death anymore. Entering the 80th day of the nine remaining circuit that lights … led glow dimmed to 50%, and I expect a maximum of 16 days ahead will die all. It is cheaper to use LED …. because I already proved myself, but it does not flame LED can last up to 3 months. Can anyone provide input for this information.

  • KC says:

    hi i am no expert and trying to build a 50 led light for outside of my property, i want to build 20 of them and need help with a good everlasting circuit? PLEASE HELP? using 230v and want to drop it down to 12v? with 25 led in series?
    can some one help with this?

  • arie says:

    Hiii Seetharaman

    I’ve been testing some settings, which you recommend. Sorry I just want the reality of course, want proof of existing range ,….. and the most efficient in terms of electricity cost savings resulting from the use of the circuit. no 1. Home … I tried a series I made with 40 LED mounted parallel, this circuit I connected to the mobile phone charger, with an output of 7-9 volts dc 600-700 ma, one room needs two series led and mobile phone charger, in order to more light (one room … means 40 led x 2 = 80 led). there are 3 rooms that I put a series of LED (80 LED x 3 rooms = 240 led). No. 2, I have one 13-watt incandescent lamp Bolam. No. 3, I make the above circuit mounted 40 series and parallel (to the truth He led 10% brighter than the No. 1 and I can place in one room). All electronic equipment in my house off and I just concentrate on three things above. I turned on the third series of items. When the flame means no 1 no 2 and 3 off …. and so on. If no 1 flame …. I looked into kwh meter …. rotation plate of very slowly ….. kwh No. 2 turns I see kwh meter 4% faster than the no 1, When the No. 1 and No. 2 flashes in unison and I compare it with … with no 3 ,….. turnover was 13 watts incandescent lamp Bolam faster 25% of the combined No. 1 and No. 2. Conclusions from the experiments that I do from no1, 2, 3 ….. for No. 1 is the most efficient (but unfortunately led is still less bright flame, no 2 …, 15% brighter than No. 1 to No. 3 turned out kwh meter lap faster than the two combined (No. 2 and 3). So the conclusion Bolam was wasteful …. 13 watts when on appeal with the lights from the LED. But unfortunately I made a series with 40 led parallel connected with mobile phone charger … requires so much led the installed … is there anything that could improve my experiment at no 1 …. to be able to burn more brightly? please help me …… thanks

  • Rahul Shah says:

    Hiii Prasad,

    I am beginner in the electronics..I want to know that how can we select the value of Resistor & capacitor for the LED lamp? pls inform me with example..Guess for 4 LED lamp..

    pls,I m Engineering student..so help me..
    My email id is rahulshah144@gmail.com

  • arie says:

    Seetharaman Hi, thanks for your information, I’ve tried to assemble 40, 60, 75 led in parallel pairs, the power supply that I use from mobile phone chargers from 6 to 7.5 volts dc, with LED lighting mounted 75 parallel are brighter than the 40, 60 led is mounted parallel, but when I plug led over 75 seeds, outbursts began to dim. I wore hand phone charger because the fare is cheaper when assembling the adapter itself, equivalent to 6 watts lamp flame. In one room I had to install two series with 75 LED flame parallel and equivalent to 11 watts. This I put in the front room, bedroom, and roads. I wear it been 35 days and is safe only, to damage from a series of 75 led in parallel .. one led outages or other circuit which led a dim,. So the damage is very small. But the series that I made it …… I was not efficient in the sense that I still use led so much. Right now I’m still trying to LED circuit attached directly to the ac 220 VLT series of recommendations from you, and I put 24 LED series … sizable 15% brighter flames from a series I created, and then I try 2 days constantly on …. and I want to see the toughness of these led ….. a day I put (on), 8 LED looks began to dim and 16 led is still burning brightly lit .. and I will continue next week. Hi Setaraman … is there any new information to me about it please inform led to me, sorry I’ve never used 20-year engineering science weak current (electronics) so I forgot a lot. Thanks arie

  • Seetharaman says:

    Hi Arie If your LEDs consume 25mA at 3.2 volt, You can connect 2 LEDs and a 39 ohms in series and connect it to 7 Volt DC supply. with 700mA supply available you can connect 28 of the above in parallel. That is you can use 56 LEDs in all with 7volt 700mA supply. With 56 bright white LEDs the illumination will be similar to 22watts energy saver lamp. Each LED consumes 80milliwatts. 56 LEDs approximately 4watts consumption. The following is most efficient.
    http://www.circuitstoday.com/mains-operated-led-circuit

  • arie says:

    Please help me, I try to assemble 60 led in parallel, with supply from the charger hp 7 v – 700ma, bright emission similar to incandescent lamps 6 watts, so it is still too dim. Question 1. How can 60 pairs of LED light in brighter paralelbisa equivalent to 15 watt incandescent lamp? 2. With the above parallel circuit 60led how many watts are generated and how is it calculated? 3. Are there any other circuit is more compact or more saves watts which released? Thanks arie

  • Fazal-e-Majid says:

    Mr. eason. you can use 50 LEDs by using C1=5uf,400V poly. use 3.6V LEDs with 25mA current.5uf Cap can safely deliver 250mA current needed by 10 strings of 5 LEDs connected parallel.

  • LEE says:

    hi Mr.Seetharaman,your comments are very helpful.thank you very muuch.

  • NJ says:

    Hi, what would the R1 and C1 values need to be to get the voltage across C2 to be 12vdc? I have an LED module with 21 LEDs that simply needs a 12vdc supply. The LED module is rated 1.3 Watts and already contains current limiting resistors to operate at 12vdc.

    Thank you.
    NJ

  • Unicorn says:

    Dear Mr John.

    I would like to make pancakes. Could you please send me an recipe for those. I would light up them with the led lamp of course.

    Please advice.

    BR,
    Tankita Tikar Al-Abesat

  • eason says:

    Sir, i would like to make a 50 LED lamp. I will have 10 LEDs per string. can you tell me the modification to be done for the circuit?

    Thank You

  • Eason says:

    Hi Tony, for the 110K resistor, what is the power rating needed? Also what is the required power rating for the
    1N 4007 diodes?

    Thank You

  • Eason says:

    Hi Tony, If i arrange 8 LEDs in a row( connected in series) and i have a total of 5 rows so ( 8LEDs* 5 rows = 40LEDs). Is this going to work ? Also i have read Nikhil Goenka’s comment on the circuit that ” after use of 3-4 weeks, the luminance of led’s drops.” How can this problem be overcome?

    Thank You

  • Humaira Naz says:

    it was nice reading the discussion. i m a electronics hobbiest. dont know much about calculations etc but i try to understand. i have a question though its not directly related to the the topic but still i think may be you could help me. i just want to know whether, high bright LEDs available in Pakistan or not? and if not, normal LEDs could serve some purpose?

  • tony says:

    Hi Seetharaman,

    Thanks for your explanation that’s really deep.

  • Seetharaman says:

    Hi Tony the above circuit is not a constant current circuit. it is just a limiting resistance for LEDs. LEDs are 3 volts 25ma bright white LEDs. Total current is 150mA through 56 ohms. a drop of 8.4 volts plus LEDs in series 6 volts. so 14.4 volts across C2 better to use a 15 volt 3 watt zener diode in parallel with this capacitor. To get constant current through LEDs in parallel use a voltage regulator for the supply and use individual resistance (470 ohms 0.5 watt) for each series group of LEDs (in the above case just 2nos in series), then it will become constant current LED drive.

  • tony says:

    Hi Seetharaman,

    Thanks for your information and searching for this circuit(circuit with resistance) but cannot find it, do you know where to get it?

    The circuit attached as above is constant current and how long the LED’s will stand ?

  • Seetharaman says:

    Hi Tony you are correct in series if one LEDis open others will not glow. if one is getting shorted the excess voltage has to be shared by other LEDs if no current limitting circuit may be few more can get damaged. with a constant currnent drive the LEDs connected in series are safe.
    by using resistance for each LED you can have a long useful life for the LEDs.

  • tony says:

    Hi Seetharaman,

    1) If one of the LED defect in series circuit what will
    happen to other LED still continue on and how long the LED
    life spend ?

    2) For parallel circuit as you said need to use resistance
    for each LED means can prolong the LED life spend, am I
    right?

  • Seetharaman says:

    Hi Tony you can use in any way but in parallel you have to use current limitting circuit (may be a single suitable resistance) for each LED, for series all have to have the same current LEDs you cannot mix up. a single constant current source can take care provided the voltage level is taken care.
    Hi Ramsing you have to use paper, polyster or poly carbonate not electrolytic with polarity. it should be non polar type. you can use normal 5mm LEDs.
    you can use the latest project appeared in circuits today which is more reliable and powerful

  • tony says:

    Hi Guy,

    Which one better LED in parallel or in series ?

  • ramsing says:

    Hi,
    I want rig up this ckt and I am new .which type of capaciter c1(In ckt)wether Electrolight or diffrent,if it is electrolight it will be having polarity (+,_)

  • ramsing says:

    Hi
    I am ram. can any 1 tell me that ckt shown above can be used for normal 5mm led or dfrent led.

  • 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

  • seetharaman says:

    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.

  • rama krishna says:

    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

  • seetharaman says:

    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.

  • V. Hari Hara Prasad says:

    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.

  • Nikhil Goenka says:

    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

  • Sathika says:

    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.

  • Seetharaman says:

    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.

  • Sathika says:

    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.

  • seetharaman says:

    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

  • Sathika says:

    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………

  • V. Hari Hara Prasad says:

    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)?

  • Sathika says:

    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.

  • gaurav says:

    can u tell how much power will it dissipate