# Mains Operated LED Circuit

john February 16, 2011 589 Comments

This is a modified version of the circuit Super bright LED Night Light published here. This circuit is submitted by Mr. Seetharaman and its full credit goes to him.

This is the circuit of a well tried and reliable 230 Volt AC mains operated 24 LEDs (super bright 50mA LEDs). While practically compare the brightness between this circuit and 11watts tube, the LED light is much better. The layout is made in such a way, you get uniform illumination. A photograph of the cicuit is also given in this post.

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• Yatin
August 11, 2011

I want 20 mA output.

• Yatin
August 11, 2011

I want to know which capacitor and register work for 72 led light.

• seetharaman
August 6, 2011

Hi Rohit use the standard formula. f = 1 / (2 pi R C) you will know the reactance for a capacitor you know the number of LEDs its current calculate it resistance you will know what is dropping resistance required. calculate C from the above formula.

• rohit
August 6, 2011

Hello Seetharaman,

A basic question,In all Mains operated circuit, the voltage is reduced by capacitance reduction, Hence is there a table some where, where
Example- a 22uf polyester capacitor would provide about 20mA of output current is displayed to make things easier.

regards

• murali
August 5, 2011

thanks sir

• seetharaman
August 5, 2011

Hi Murali change 1uF to 1.5uF. change both 100 ohms to 47 ohms 2 watt. up to 24 LEDs you may not see much change in illumination

• murali
August 5, 2011

Dear sir
i want to make one 10leds and another 16 leds of 8mm, 0.5 watts 100ma leds what are the changes is requir, please help me.

• murali
August 5, 2011

Dear sir
i want to make one 10leds and another 16 leds of 8mm, 0.5 watts 100ma leds what are the changes is requir, please help me.

• seetharaman
July 28, 2011

Hi Kumar Blue is 1uF 400volt polyester / poly-carbonate and orange is 10uF 160volts electrolytic. it is available in Bangalore and Chennai.
Hi Mudassar check your bridge rectifier polarity and check the 1uF it should be non electrolytic check the polarity of 10uF 160volts. If all are OK your bridge rectifier diode may be faulty or connected wrongly.

• Kumar
July 27, 2011

Hi, Sir what type of capacitor need to be used in above mentioned circuit diagram (10uF 160V) its ploy or some other type. If its 10uF 160V Ploy in above mentioned 3 pictures in 2nd picture what is that blue capacitor used and whether its available in India (Bangalore).

• Mudassar
July 27, 2011

HI sir i assembled this circuit but voltage across bridge diode is 5.3 and voltage across 10uf capacitor is zero,means no voltage, i am using 1uf/250v capacitor, please suggest me the solution, waiting for reply

• seetharaman
July 27, 2011

Hi Kumar if you keep the LED circuit open and switch on, a peak DC of 325 volt will appear across the capacitor and blow it. use 400 volt if you are not confident of your wiring. if the circuit is fully connected without any mistakes then LEDs will glow and capacitor will work without blowing, as the voltage developed across the LEDs are just 72 to 80 volts only.

• Kumar
July 26, 2011

Hi, 10uF 160V Capacitor got burned why is this problem happening already 3 capacitor got brunt.

• Saifur
July 18, 2011

Thanks dear

• seetharaman
July 8, 2011

Hi Saifur the protective resistances have got burnt(120 ohms). This indicates over current drawn by the circuit. This is due to the capacitor 474K. the voltage rating of the capacitor may be low. try to get 400 volt capacitor and use. the 120 ohms 1/2 watt is more than sufficient. with 474K capacitor the current will be 25ma. 25ma through 120 ohms will be hardly 100milli watts.

• Saifur
July 3, 2011

Dear please check those photos, you may get a clearer view

• Saifur
July 3, 2011

“what is the current consumption at 3.2volt” I cannot get your question

“What about 10uF 160volt and 1N4007 are they healthy?”

10uF 160volt is burned, and 1N4007 are looking normal, but I don’t know, I give those pictures for your advice

_______________
June 26, 2011 at 8:32 am
You Said:
Hi Saifur These diodes are rated for 3.2 volt @ 20mA. reduce the capacitor from 1uf to 0.47uF. no other modification is required.

________________
I check Led’s packet, & found that they are 3.2 volt, But I cant remember what mA are written in those LED’s packet

____________
I will make this ckt again, But afraid of burned again

• seetharaman
July 3, 2011

Hi Saifur what is the current consumption at 3.2volt. What about 10uF 160volt and 1N4007 are they healthy?

• Saifur
July 3, 2011

I check LED specification, It is 3.2 volt LED

• Saifur
July 3, 2011

Please give me some suggestion, so that when I make this project again , then it will not burned.

• Saifur
July 3, 2011

Dear, today it is not on at all, then I check it, and found it burned, What is you thinking about it? I give some pictures of it, Burned pic, A set of parts,

http://imageshack.us/photo/my-images/17/dsc00013zq.jpg/
Another set of parts,

http://imageshack.us/photo/my-images/811/dsc00015fn.jpg/
Burned View again

I will make it again, want your advice, that It will not burned again, Waiting for your advice, You may guess something after viewing these pictures

I was happy to make such light by my hand which will consume less current.

Dear I appreciate your effort of helping us

• seetharaman
July 3, 2011

Hi Saifur either your 1N4007 are defective or the LED specifications are different. the same is working in my house for last more than a year without and deterioration. in India we found that to be due to defective 1N4007 replacing them with reputed make,made it ok, no LED has failed. you can also remove LEDs feed 3.2 volts and check for the operation of each one if they are good the problem is 1N4007 only.

• Saifur
July 2, 2011

dear, I made it with your support, & at first It gives nice light, but continue running after 2 hr, It goes totally dim ,

when I switched off the light, then it stops slowly,
What is the problem do you think?
waiting for your support. Now I am frustrated.

• Saifur
July 2, 2011

• seetharaman
July 1, 2011

Hi Saifur the photos are out of focus, anyway 474 means 470000 that is 470KPF or 0.47uF. if it is rated for 400 volts you can use it.

• Saifur
June 30, 2011
• Saifur
June 30, 2011

Dear seetharaman, I am facing some problem,
as ur suggestion, I buy this capacitor, (seller give me this) check this link . It is correct capacitor? I am confused. you said 1uf to 0.47uF 400volt. But seller give me 1H 474K.

Please check this link to view pic of this capacitor. It is correct one?
http://img715.imageshack.us/img715/3948/capqc.jpg

• seetharaman
June 26, 2011

Hi Saifur These diodes are rated for 3.2 volt @ 20mA. reduce the capacitor from 1uf to 0.47uF. no other modification is required.

• Saifur
June 25, 2011

Dear Seetharaman
If I use normal 2 pin white LED, is there any problem arise? I am afraid that I will not find that 4 pin bright white LED in my Bangladeshi market. Though I am new, forgive my this type of question

• Saifur
June 25, 2011

** 2 pin white LED

• Saifur
June 25, 2011

Dear Seetharaman
If I use normal 2 pic white LED, is there any problem arise? I am afraid that I will not find that 4 pin bright white LED in my Bangladeshi market. Thought I m news, forgive my this type of question

• seetharaman
June 25, 2011

Hi Capsun it is due to surge voltage and current.
to avoid this zeners and filter capacitors are used. Still if it is happening the LEDs may not be of the rated capacity. Any standard reputed retailer will be in a position to help you.

• capsun
June 25, 2011

Pls tell me which company capacitora,diodes are best.i found some of the LEDs are burning after swiching it on and off several times.May i know the reason for this.

• seetharaman
June 24, 2011

Hi Capsun Replace the polyester capacitor with a good quality 400volt capacitor.

• capsun
June 24, 2011

Dear SIr Iam using PCB ,The problem is the brightness is not uniform they are becoming dim for a while and again they become bright.The poly cap becoming very hot.What changes i have to make .Waiting for reply

• seetharaman
June 24, 2011

Hi Capsun 16 LEDs of 3.2 volt is 51.2 volt and each LED dissipates 3.2 X 0.13 = 400milli watts. you have to use proper heat sink PCBs for them. if the generated heat is not properly dissipated they will fail.

• capsun
June 23, 2011

Dear Sir they are also becoming dull for few minutes and again become bright .The brightness is not constant.Pls tell me whats wrong in my circuit .Waiting for reply

• capsun
June 23, 2011

Dear Sir I have connected 16 LEds (3.2v @130mA) in series .I Increased 1 mfd to 2 mfd, added 33v 1 watt zener 2 in series and parallel to filter also changed 100 ohms to 47 ohms but the LEDs are burning out after few hours.Zener diodes also become fail.What changes i have to make . pls tell me . Waiting for reply

• Seetharaman
June 21, 2011

Hi Saifur the above circuit is the corrected one after June 26th the mistake was corrected. yes they are 4 Pin Hi Bright white LEDs 3volt at 50mA.

• Saifur
June 20, 2011

see this picture.. I cant recognize problem in that & your b rectifier, Please clarify dear as I m new.

Is these white LED’s are 4 pin?

as I am new, so I arise this type of question. Waiting for your asnwer

• Saifur
June 20, 2011

Dear Seetharaman
I am new in electronics, but I can follow the circuit. But in some comments (June 26, 2010 at 2:27 am) you said there is some problem in this ckt, & some diagram may rotate 90 degree. Do you please clearly and corrcet the diagram pls so that I can directly follow the diagram

• CHETAN
June 18, 2011

Sir, I added extra 12 LED’s that is total of 36 LED’s the brightness has been increased.. thank you..

• CHETAN
June 17, 2011

OK sir thank you..

• Seetharaman
June 17, 2011

Hi Chetan the same circuit will do. no change is required. As the change in current flow through the LEDs are marginal you will not practically see any brightness change.

• CHETAN
June 16, 2011

sir, for 36 LEDs (3volt @ 50mA) what modification I’ve to make..

• Seetharaman
June 16, 2011

Hi Capsun 24 Hi-bright white 4 Pin LEDs (3volt @ 50mA)in 2 rows will replace 11watt PL lamp. 40LEDs in 3 rows will replace 23 watts CFL lamp. May be for 15 watts you require around 30 in 3 rows to take care.
Hi Chetan the same circuit will do for 3.2 volt 50mA Hi Bright 4 Pin LEDs..

• CHETAN
June 16, 2011

Sir, i want to add extra 12 LED’s that is total of 36 LED’s What changes I’ve to make..

• capsun
June 15, 2011

Dear Sir I want to replace 15w CFL with LED .How many LEDs i have to use to get same brightness as 15w CFL. What kind of LED should i use .Waiting for reply

• Seetharaman
June 15, 2011

Hi Chetan see the figure in the following site. you get the same in India.

• Seetharaman
June 15, 2011

Hi Chetan there is a PCB mount available for 150mA LEDs costing around INR 10, you have to use them for each LED.

• CHETAN
June 15, 2011

Sir, what I have to do for the heat sink..can you give me some suggestions please..

• Seetharaman
June 14, 2011

Hi Chetan you have to use the PCB with heat sinking track meant cooling these LEDs.
Hi Anish Please refer the General purpose PCB
http://www.delabs-circuits.com/cirdir/electric/electric2.html

• June 14, 2011

Thanks for the reply sir, definitely the bread board is my fault. I have the correct components. where do we get glass fiber pcb’s? and how do they look like? this is the first time i am hearing that name..

• CHETAN
June 14, 2011

Sir, the LED specification are:-
Max. Forward Current: 150mA
Max. Forward Voltage: 4.0V
Working condition: -40°c~+60°c

• Seetharaman
June 13, 2011

Hi Anish phenolic bread boards insulation value can handle say up to 100 volt but not greater than that. Hence you use a general purpose glass fiber PCB which can take care. Check the diodes and electrolytic filter capacitor and the 1uF capacitor it should be rated for 400volts. ensure that you are using high bright white LEDs with 50mA @ 3.2 volts.

• June 13, 2011

Hi,
I assembled the circuit, and when powered, the .5 watt resistor connecting the bridge and mains power burnt..(and was burning till i cut the power).. cant troubleshoot the problem.. what may be the possibilities? My friend suggested not to use it on the bread board..
IMO, using bread board is the fault?

• Seetharaman
June 12, 2011

Hi Capsun For 16 LEDs you have to use an electrolytic filter capacitor of 220uF 63 volt use 2nos 33volt 1watt zener diodes connected in series and parallel to filter capacitor as surge protector. Use 2uF capacitor instead of 1uF in the supply input.
Hi Chetan Check your LED specifications. test one led with 80mA constant current if it is getting heated up, you require PCB type heat sink for your LEDs. LEDs are around INR30 and the special PCB is INR10.

• CHETAN
June 12, 2011

Sir, the LEDs are becoming very hot..

• capsun
June 12, 2011

Dear Sir how to choose the voltage of the electrolyte capacitor .I want to connect 16 LED in series (3.2V@ 130mA).What other components i have to change.Waiting for reply.Thank u

• Seetharaman
June 11, 2011

Hi Chetan no change is required the same circuit will do.

• CHETAN
June 11, 2011

Sir, what changes I have to make to get 80mA..

• CHETAN
June 10, 2011

Ok sir i will use polyester type.

• Seetharaman
June 10, 2011

Hi Chetan you have to use non polar type, since it is used in AC circuit, getting 1uF non polar electrolytic will be difficult but 1uF polyester is available in plenty in the market, which you can comfortably use.

• CHETAN
June 10, 2011

Sir, can i use 1uF 400v Electrolytic capacitor or polyester type capacitor.

• CHETAN
June 10, 2011

Thank You Sir…

• Seetharaman
June 10, 2011

Hio Chetan for 80mA LEDs no change is required.

• CHETAN
June 9, 2011

Sir, i want to get 80mA because 120mA will be high for those LEDs.. So what modification i have to make.

• Seetharaman
June 8, 2011

Hi Chetan you can use the same circuit with 24 LEDs of 3.2 volt 120mA 8mm straw hat LEDs. the total power consumed by 24 LEDs will be around 10watts (with 1.68uF).

• CHETAN
June 8, 2011

Sir, so that how much current it will dissipate in each LED and can I use 8mm 0.5 watt straw hat LED..

• Seetharaman
June 8, 2011

Hi Chetan increase 1uF polyester to 1.68uF(add a 0.68uF 400volt parallel to 1uF)

• CHETAN
June 7, 2011

Sir, I want to make another circuit…
In the above circuit can i use 8mm 0.5watt straw hat LED which can withstand upto 100Ma..

• Seetharaman
June 7, 2011

Hi Jawad use Light from scrap circuit you can use up to 13LEDs without changing any component.

June 7, 2011

dear sir,
I want to diagram which used 8 Leds on direct 230 vac

Thanks,

• vysakh
June 5, 2011

@seetharaman, what happen to john??? No new posts here and one of my post under pending?

• Seetharaman
June 5, 2011

Increase 1uF to 1.64uF (use 2nos 0.82uF 400volts in parallel). reduce 100 ohms to 47 ohms 2watts. all other components require no change.

• capsun
June 4, 2011

Dear Sir I want to connect 10 LEDs (3.2v@ 150mA) in series .Pls tell me what changes shall i make in the circuit.Waiting for reply

• CHETAN
June 4, 2011

Thank you for your kind response sir.

• Seetharaman
June 4, 2011

Hi Chetan This circuit will consume around 2.5 to 3watts.

• CHETAN
June 4, 2011

Yes sir, the LEDs are getting little warm.. Sir, i want to know how much watt it will consume..

• Seetharaman
June 3, 2011

Hi Chetan readings are looking alright. run the light for about 2 to 3 hours. switch off and check the leds are they little warm or hot. it should be just little warm indicating everything is fine.

• CHETAN
June 3, 2011

Sir, I have used 24 LEDs. The DC voltage and current across EACH LED is 3.14 volt and 17 mA.

• Seetharaman
June 2, 2011

HI Chetan how many LEDs you have used? If possible measure DC voltage across one LED. With 1 or 2 LEDs it will be 24mA. with 24LEDs it will just less than 20mA.

• CHETAN
June 1, 2011

Hi sir, i constructed this circuit by using 0.33uF capacitor for 3 volt 20mA LED’s as you said, and they are very bright I don’t know how much current is flowing through those LED’s..

• Seetharaman
May 26, 2011

Hi Adru to get 40volt at 1amp you require around 12uF 350volt AC capacitor which will be rare to get and will be quite expensive. these circuits are suited for a maximum value of 2.2uF capacitor i.e. max 120mA at 40 volts. Hence for higher currents use transformers or switching supplies which are best suited.

• Seetharaman
May 26, 2011

Hi Chetan reduce 1uF to 0.33uF, no other change is required

• Chetan
May 25, 2011

Sir, i want to connect 3v 20mA Leds what modifications I have to do. please reply sir because I will construct this one.

May 24, 2011

WOW wat an active post & itz being one year nearly;regards for sir.seetharaman,mouly,japanjot.
i hv one question:
can v use this circuit as a transformerless dc powersupply for digital circuits,say design it for 40v 1A and placing an LM317 for varying the dc output voltage 1.2-37v.

Atually i dont want bulky transformers :-p

• Seetharaman
May 14, 2011

Hi Rajesh 474K, first two are integers like resistance code 4 indicates 10 to the power four as multiplier (simply add 4 zeros) hence it is 470000 pF or 470KPF or 0.47uF. K stands for 5% tolerance and J stands for 5% tolerance.

• Rajesh Misra
May 13, 2011

Sir, how can we read the coding in Polyster capacitor? 474K/400v, 400V474J…etc….

• Seetharaman
May 11, 2011

Hi Misra 25mA LEDs will get damaged.

• Rajesh Misra
May 10, 2011

sir,
can i use 50mA & 25mA LED’s mixed in these circuit? is there will occur any problems?

• Seetharaman
May 9, 2011

Hi Benny if want full kit you can contact DJR Electronics Chennai. 04442028443, or components without board from Vegakits Mumbai.

• benny
May 9, 2011

Dear Mr.Seetharaman sir, i am interested in this circuit very much… but i am located in a rural area of ponpara ….so the scracity of such electronic components is facing here,,,,, sir, are you a shop dealer of the electronics goods/ electronic items…? i am ready to make payment for the components of the device / please tell me where i can get these components by courier? i am ready to make payment in advance. So please…please help me////

• Seetharaman
May 4, 2011

hi Nikolas the bridge circuit is already corrected in the above diagram. what is shown now is correct

• nikolas
May 3, 2011

Sir Seetharaman, I’d like to ask a silly question (Im a newbie in electronics):
Why the bridge should be rotated 90 degrees clockwise? Is the bridge differ from http://www.circuitstoday.com/mains-operated-led-lamp?
Thanks.

• Seetharaman
April 30, 2011

Hi Meodenmatula Use 1uF only or else you will loose your LEDs soon. with 2.2uF the current will be greater than 110mA for 50LEDs.

• meodenmatlua
April 28, 2011

Hi Seetharaman
I want use 220 Volt AC with 50LED 50ma.
Can i replace capacitor 1uf by 2.2uf. in addition, need to change anything else
Thanks

• Seetharaman
April 28, 2011

Hi Capsun for 20 X 1 watt LEDs. Read my reply to Mouly but change capacitor to 4.2uF 400 volts instead of 3.6uF. Any way I will recommend you to connect 4nos 1 watt leds in series, like this you make five sets connect them in parallel and connect it to a readily available 12volt 2amp SMPS.

• capsun
April 28, 2011

Hello Sir,I want to make a compound light with 20 high power 1 watt LED’s.Iam new to electronics .what changes i have to make in this circuit.Please help me.Thanks in advance

• Seetharaman
April 28, 2011

Hi Mouly You have to use 3.6uF 400 volt in place of 1uF. Use 33 ohms 5 watts in place of 100 ohms. Change 10uF 160 volt to 47uF 400volts.

• Mouly
April 27, 2011

Dear Sir, I want to coneect 5 high power LED’s (3.2V @350mA) in series.Pls tell me what all the necessary changes i have to make in the circuit.Waiting for reply

• Seetharaman
April 26, 2011

Hi Mouly These depends on the make used. Reputed makes may even work for 5 to 10 years. For high voltage protection add 78volt 2watt zener (2nos 39volt 1 watt diodes in series)diode in parallel with 10uF.
Hi Rajesh no change is required except 10uF from 160 volt to 250 volts. no cooling fan is required. use a PCB with thick wider copper track and with good quality soldering should help dissipating the heat generated nicely.

• Mouly
April 26, 2011

Dear Sir ,what is the life span of the poly capacitor,also the 10uf electrolytic capacitor.How long they work ?Can this circuit withstand high voltages?Waiting for reply

• Rajesh Misra
April 9, 2011

Hi Seetharaman sir, i created the above circuit for outdoor use with a 8 x 8 Matrix in a PCB, all the LED’s are 50mA. What are the other changes should i made in the above said circuit for the 50mA LED x 64 nos? please clarify the poly. cap values and other resistor/ capacitor values. I planned to place in a closed outdoor light fitting to safe it from rain. Should i add some cooling fan’s for the 64nos included? Please clarify…. thanks in advance for your valuable reply

• Seetharaman
March 29, 2011

Hi Mohanraj
use both the foromulae for your calculation, use RMS value.
the values are 230 volt 50Hz.
use the formulae
R = V / I (the voltage you want to drop with current flow required) AND substitute R in the following formula.
f = 1 / (2pi R X C) to calculate capacitance.

• mohanraj
March 28, 2011

Dear sir

How to calculate capasitance value and all resistor value in the above circuit diagram if there is any formula for each please replay me sir

• Seetharaman
March 3, 2011

Hi Arie this circuit is suitable for 50mA hi bright LEDS which can stand 75mA. If you are using Hi bright whie 25ma LEDs donot exceed 35mA. Hence I will prefer you to reduce 1uF to 0.47uF. Check 1N4007 diodes some consignments available in the market are bad, they cannot stans more than 100volt. May be 1N4002!?. my prototypes (10 pieces) still running safe at home. The brightness is much better than 11watt energy saver u type tube.

• friend
March 3, 2011

ARIE, dont use mic make diodes, use other makes which has thick leads. And the above ckt works without any problem if u use quality components check ur LED voltage and current this circuit is for 3.2v,50mA. if ur LED’s are 20mA it i’ll get fade soon…

BENOY if u r using 2core cable for 4ft then the conductor loss may present. it,d be better if u use fine thin wire bcos it has less copper so loss ll be less

• arie
March 3, 2011

hi, I am trying to string it, for R.. I replace it with 1 watt. I tried it just two days … with the condition led to live, not hot component, but on the first day .. 8 led start to fade, for 16 other led is still burning brightly. And flame equal to 24 LED lights 7 watts, still less bright? and how many led to the pair to be burning brightly?. how the power output by 24 led?

• Benoy
March 1, 2011

Hi Seetharaman sir, Primarily a Hats off! I’m eagerly searching for a LED Lighting sys for my ‘dark’ room( actually an extension of my home is become cloudy with out proper windows!). I found it.. Am in doubt that can I set the 24 no. series with a 4 feet partitioning? ie, shall i set the LED’s series in 2 by lagging the 12 LED’s after 4 feet gap(with a 2 core cable? is it will make any wrong result? Please reply

• Seetharaman
February 26, 2011

hi pramugan 5uF is capable of 360mA current. since you have used a 50volt capacitor it has become leaky above that voltage hence 50 / 3.2 = 16 LEDs can glow beyond that the capacitor should have become hot.
with 160 volt capacitor 160 / 3.2 around 50LEDs. the filter capacitor is acting like a resistance at higher voltage.
in the above circuit with 5uF 350volt capacitor in the input and 10uF 350 volt as filter you can connect 108 LEDs in series.

• Pramugan
February 26, 2011

when i ll be getting reply for my post

• Kumar
February 23, 2011

yes mouly calculate the capacitance value according to ur requirement.

• Mouly
February 23, 2011

Dear sir
Is that possible to get output above 150mA so that i can light up high power LEds in series from the mains supply

• pramugan
February 22, 2011

sir my doubt is by changing filter capacitor will the output increase?. because i construct bridge with 5ufd 400v as input capacitor and 1000ufd 50v as filter it can able to lightup 16 LEDs i replaced the 1000ufd 50v with 63ufd 160v it can able to lightup 48 LEDs.(all connections in series). in general is that possible in similar circuits?

• Kumar
February 18, 2011

thank you sir

• Seetharaman
February 18, 2011

Hi Kumar use 2nos 40volt varistors in series in parallel with 10uF 160 Volt.47uF will get still hotter. use a good quality 160 volt or use 10uF 250volt. nothing is required at the bridge input if you ate using in DC.

• Kumar
February 18, 2011

the varistor avail is 40volt and next to that is 175 volt. instead of that 75 volt 1 watt and 3.3 volt 1 watt zener in series and in parallel with 47uf 160 volt( i replaced 10uf 160volt with 47uf 160volt bcos 10uf became very hot). And should i have to connect both mov at bridge AC input and zener at filter capacitor?

• Seetharaman
February 17, 2011

Hi Kumar Your poin 1 is ok, for SMD LEDs you can use normal components no need for smd components. you can use a 270 volt varistor across the bridge rectifier AC points( input surge protection). 2nos 30 volt 1w and 1no 18 volt 1w zeners connected in series in parallel with 10uF 160 volt capacitor(towards 1uF capacitor leakage protection) or you can use a 76 volt varistor if available readily. s10k320e is a 320 volt mov. should not give any problem not suited for this circuit as it may not protect.

• Kumar
February 16, 2011

•Hi sir, I tried your circuit its working great . i used 5mfd @ input for 150 Led’s. 50 in each row.

1. how to specify the suped flux 5mm Led which
is displayed in the above picture 07 does it has any model number?.

2.if i use SMT Led can i use the same circuit or should i have to go for SMD components?

3.how to use VARISTOR in the above circuit ?

Thanks a lot for sharing ur valuable time and ideas..

i connected a mov S10K320E b/w ph and netural but it made all the LED’s to dim so i removed it what is the value i should go for and where to connect it.

• pego
February 16, 2011

i don’t have 1uf 400v. could i use 1uf 250v? is it safe or will be burning?

February 16, 2011

250V is just ok, try to get a 400V one.

• Kumar
February 16, 2011

i connected a mov S10K320E b/w ph and netural but it made all the LED’s to dim so i removed it what is the value i should go for and where to connect it.

• Kumar
February 16, 2011

Hi sir, I tried your circuit its working great . i used 5mfd @ input for 150 Led’s. 50 in each row.

1. how to specify the suped flux 5mm Led which
is displayed in the above picture 07 does it has any model number?.

2.if i use SMT Led can i use the same circuit or should i have to go for SMD components?

3.how to use VARISTOR in the above circuit ?

Thanks a lot for sharing ur valuable time and ideas..

• srundenggosong
February 14, 2011

thanks nice posting

• RAHUL
February 14, 2011

yup thank u…

• Seetharaman
February 14, 2011

Hio Rahul the required effective 750 ohms is given by the capacitor(this will be effective resistance value of the capacitor at 50 Hz). There is no need to calculate 100 ohms 2nos value, as it will be standard for all circuits to limit in rush current to 1amp max. hope i am clear

• RAHUL
February 14, 2011

i got it sir 4.7mfd and resistance is b/w 200 to 470k

• RAHUL
February 13, 2011

sir waiting for ur reply plz help me out

• RAHUL
February 13, 2011

• RAHUL
February 13, 2011

thank u sir actuallt i need to improve brightness so am adding 150 led’s of 3.5v@ 25mA 50 in each row. am confused with the calculation.50×3.5=175. 230-175=55. 3 rows in parallel so 25mAx3=75mA.since parallel current varies. so 55v @ 75mA, 55/0.075=733.34 ohms. in f=1/(2*pie*R*C) R= v drop/I =55/.075=733.34 ohms. then 50=1/(2*3.14*733.34*C) =4.3mfd. therefore standard values are 750 ohms and 5 mfd is this correct?.

• Seetharaman
February 13, 2011

Hi Rahul you require 1.2uF and 200 ohms only 3k is not required. say you are using 16 LEDs of 3.0 volt 50mA 48 volt at 50 mA you have to drop 230 – 48 volt that is 182 volt at 50mA (RMS value used for calculation) hence 182 / 0.05 that is the series resistance required. 3.64K ohms. this is Xc now calculate the required C from this freq is 50Hz. for 50 Hz thumb rule for filter capacitor is 1000uF per amp of load, for 50mA load 50uF is required to reduce flicker. 10uF is practically found sufficient without any noticeable flicker. To avoid switch on surge current to be well within the limit of 1amp 220 ohms is the preferred value.
Hi Ketha it is possible. we are trying to limit it to 90 high bright LEDs (30 in each row)with a rotational possibility of 90deg continuously, it will appear soon.

• sathya
February 12, 2011

sir i used 25 white led in a energency light light and i used 5 x 1.2v 2200mah batteries and i connected 4.7 ohm’s 10watts resistance due to this the battery drains very quickly how to modify the circuit. charging side is working good.but load side is worst. plz help me out.

• rahul
February 12, 2011

how to calculate filter capacitor sir (ie. 10mfd 160v). i designed a circuit with 680 and 1000mfd 50v for 16 led’s. without knowing the calculation only i did but its working fine, but i think its a bigger value for the ckt. i used 105j 400v poly parallel with 1k ohm and 56 ohm mext to the bridge. i just want to know how to calculate it.

• rahul
February 12, 2011

if my calculation is correct t have to use 1 or 1.2mfd and 3k resistance. before bridge.isn’t sir. and the remaining two 100 ohm’s and filter capacitor should remain the same. am i right sir??

• Seetharaman
February 12, 2011

Hi Rahul you kindly go through my comments dated nov6th and 16th will give you the details

• ketha
February 12, 2011

sir it is possible to design led tube circuit as in this link http://www.leds.edn.com/blog/leds-blog/what%E2%80%99s-inside-led-tube-light-teardown

• Rahul
February 12, 2011

from input
1st set |->->->-|
2nd set |->->->-|
3rd set |->->->-|

• Rahul
February 12, 2011

hi sir
i just want to know that how to calculate poly capacitor farad and voltage. and if i construct the circuit for 60mA is that possible to connect 50 led in a set and 3 sets in parallel. |->->->-|
|->->->-|
|->->->-| like this .

• Seetharaman
February 11, 2011

Hi Prasanth intially like energy saver lamp it will be expensive but on the long run it will pay back on electricity expenses.
Hi Dhruv you can use higher wattage resistances if space is not at premium.

• dhruv
February 10, 2011

hi sir im new to electronics and i like your project very much i just want to know that in any circuit or in your circuit also can i use high wattage resistor even circuit required low wattage resistance….in ur circuit can i use both 100 ohm resistor or 0.5 watts….instead of one 0.25 watt 100ohm resistor…waiting for ur reply sir

• Prashanth
January 13, 2011

Thanks a ton Mr.Seetharaman!
I was searching for such a thing for a long time. I will now replace all the bulbs in my home 🙂 wondering if it would be economical to do so.

• UDAYAKUMAR .S
January 12, 2011

Dear Sir,

The LED circuits are very interesting and use full to me. I hope you will publish low cost LED circuit diagrams later.
Thanking you
yours faithfully,

UDAYAN

• Seetharaman
December 10, 2010

The LEDs are High bright white 3volt 50mA type. 1uF should be non electrolytic, paper, polyster or polycarbonate. Open circuit DC at bridge rectifier output will be around 350volt. but if all LEDs and components are connected it will be around 72 to 75 volts only.

• rahul porwal
December 9, 2010

i also tried the new version but i am getting the voltage about 230 v at load.
is it correct?

• rahul porwal
December 9, 2010

ok thnx sir,

Q…. we have to use the electrolytic capacitor{1 mf 400v} only or we can use any other.
and plz tell me the voltage at the o/p of bridge,and also tell me the voltage and current rating of the LED.

• Seetharaman
December 9, 2010

Hi Rahul there was a mistake you kindly see my earlier comment of june 26th on that, it has to rotated clockwise by 90deg. otherwise the circuit is ok and functioning well.

• rahul porwal
December 9, 2010

how the bridge is working ?
plz tell me

• eason
November 18, 2010

Hi Sir, can i add LEDs until it has 36 LEDs in series? What are the components value to change?

Thank You
Eason

• Seetharaman
November 17, 2010

Hi Japanjot you can suitably adopt battery charger using SCR circuit appeared earlier in circuitstoday. use the following link.
http://www.circuitstoday.com/battery-charger-circuit-using-scr

• japanjot
November 17, 2010

ok sir,thnx for the battery charger advice, sir also tell me how to make it overcharge prtective, like the battery should stop charging when the battery is full

• eason
November 16, 2010

Hi Mr Seetharaman, can i add more LEDs to increase the brightness? Can i have a circuit that have two parallel strings with each strings having 20 LEDs(Total LEDs will then be 40).

Thank You

• Seetharaman
November 16, 2010

Hi Murali use both the foromulae for your calculation, use RMS value.
the values are 230 volt 50Hz.
use the formulae
R = V / I (the voltage you want to drop with current flow required) AND
f = 1 / (2pi R X C)

• Seetharaman
November 16, 2010

Hi Murali you can use as indicated by me on 15th Nov.
Hi Satyam this is a standard formula available in any text book. f=1/(2*3.14*R*C)

• Satyam
November 16, 2010

Hello Sir, your formula is not so clear, Is it f=1/2*3.14(pi)*R*C OR f=1/(2*3.14*R*C)

• murali
November 16, 2010

all leds r 3.2v max 3.6v

• murali
November 15, 2010

all leds r 3.2 to 3.6 voltage sir

• Eason
November 15, 2010

Hi Mr Seetharaman, can i add more LEDs to increase the brightness? Can i have a circuit that have two parallel strings with each strings having 20 LEDs(Total LEDs will then be 40).

Thank You

• murali
November 15, 2010

thankyou sir yes iam planning to use 5mm 3v 20ma, help me for 24led & 36led of same rating

• Seetharaman
November 15, 2010

Hi Murali use 0.68uF for 1uF all others don’t require any change. (hope you are planning to use 3volt 20mA white LEDs).

• murali
November 15, 2010

i want to connect 48 5mm leds of 20ma each what should i change in this circuit please tell me sir

• Seetharaman
November 11, 2010

Hi Japanjot yes you can make it. 1.3AH battery requires 130mA charging current now calculate for 130mA RMS current that is 230 / 0.13 with 1.8mF you can get it. if not you can use available 2uF or 1uF 2nos in parallel. instead of LEDs you connect the battery. use a 4.7 volt zener to limit the battery terminal voltage from raising.

• japanjot
November 11, 2010

ya i checkd they are of 3.2v 25ma, sir how to charge 4v battery of 1.3 amp, i want to charge it around 150ma per hour, i want to make transformerless supply like this for it.thank you

• Seetharaman
November 11, 2010

Hi japanjot congrats. hope the LEDs are 3.2 volt 25mA that is 0.025A, your calculation is also correct for peak current calculation.

• japanjot
November 10, 2010

and sir while calculating R for f=1/2pi.R.C the voltage i used is 320v for calculating v in v=ir,320 v dc v

• japanjot
November 10, 2010

sir i am running 100 blue leds in series, and all i modifies is just i added 3.3uf cap parallel to 1uf cap in your circuit, the total power is around 5w, and leds are quite bright
the leds which i used were 3.17 to 3.20v @ 0.22-0.28 ma
thnks sir 4 this usefull ckt

• Seetharaman
November 7, 2010

Hi Japanjot you try and give me a feed back about your success.

• japanjot
November 7, 2010

*=>>sir with 2uf cap can i connect 60×2 chains of blue led of 25-28 ma ???? total of 120 leds?

*=>> sir what is the maximum limit of dc voltage which we can use for leds ??? when i check o/p voltage withot load its around 345v, so can i use 100 leds in series(3v each and 30ma current) to utilise 300v out of 340 with 2.4uf capacitor??

• Seetharaman
November 7, 2010

Hi Japanjot. The 100 ohms are only for input current limitation they donot require any change. The discharge resistance can be any value from 100 to 470 K such that they dont add up the current flow and dissipate power. 10uF will remain the same.

• japanjot
November 6, 2010

*=>>sir with 2uf cap can i connect 60×2 chains of blue led of 25-28 ma ???? total of 120 leds?

*=>> sir what is the maximum limit of dc voltage which we can use for leds ??? when i check o/p voltage withot load its around 345v, so can i use 100 leds in series(3v each and 30ma current) to utilise 300v out of 340 with 2.4uf capacitor??

*=>> how to calculate capacitor’s discharge resistor. and other two resistors and their wattage (100ohm 0.5w in your ckt)
thank you sir , you always reply with patience

• japanjot
November 6, 2010

one more thing sir, how much volts can we use for leds, like for 24 we using 72 volts , can we use till 230 volts for 76 leds?

• japanjot
November 6, 2010

ok thank you sir now my circuit is working fine i am using your same circuit with 2 parallel chains of 28 blue led total 56 leds, they are absolutly fine. thank you

sir how u calculate resistance which is parallel to capacitor?

and if the dropping resistor value comes to be 6 kohm, then do i have to change all the 3 resistance to 6 k ohm or the one which is directly connected to 230v(100 ohm in your ckt) or the resistance which is next to the bridge(100 ohm in your ckt) ?

and the 10 uf cap would remain same in all the cases i guess?

• Seetharaman
November 6, 2010

Hi Tony with the recommended LEDs connected the terminal voltage cannot raise beyond 72 volts. by using a low current LEDs the drop across capacitor 1uF will be less hence high voltage will appear across the capacitor and inturn on LEDs. as lesser drop across capacitor higher voltage has devoloped highed current for the LEDs hence they have blown.
please go through the calculations i have given earlier today.

• tony
November 6, 2010

Hi Seetharaman,

If rotated by 90deg than the output voltage at this point capacitor 10uf 160v will be very high 228v – 230v without attached to LED’s and this capacitor start become hot.

No wonder Mr.Japanjot LED’s burn.

• Seetharaman
November 6, 2010

Hi Tony in my above circuit the bridge rectifier has to be rotated by 90deg it is a mistake.

• tony
November 6, 2010

Hi Seetharaman,

I tested all the component is o.k, it is because of the diode direction (1N4007) ?

• Seetharaman
November 6, 2010

Hi Tony it looks your capacitor is shorted, reason without load the peak terminal voltage can raise to 230 X 1.414 = 325 volts. hence you have to use a 400volt capacitor without load. if loaded 160 is sufficient as you are likely to get around 75volts.

• tony
November 6, 2010

Hi Seetharaman,

I try to assemble the circuit as above and I measure the DC voltage 0 no reading at capacitor 10uf 160v, do I miss something I’m using 1N4007 diode. What is the reading at this point before connecting to LED.

• Seetharaman
November 6, 2010

Hi Japanjot This circuit will work with 3 volt 50mA BRIGHT WHITE LEDs. If you want for any other current you have to recalculate. Say you want to use 25 blue LEDs of 4 volt @ 25 mA. 4 X 25 = 100volt at 25mA your supply voltage is say 250volt at 50Hz. Now you have to drop 250 – 100 = 150 volt. 150 volt the current through is 25mA then the dropping resistance value is 150 / .025 = 6 kilo ohms. by using the formula the capacitance required is 0.53uF use a standard nearby available value 0.47uF, by which the current will get reduced to 22mA which will not reduce the glow appreciably, also safe for the LEDs to be driven with slightly lower current.

• japanjot
November 5, 2010

sir happy diwali to you and your family, wish u had eco frndly diwali with led lyts 🙂

• japanjot
November 5, 2010

helo sir, i made dis circuit with blue 25 leds it workd fine for first time, but as i switchd of and again powerd on all the leds got burnt :-(…… sir wt to do??
sir plz explain me how to imply your formula f =1/2piR.C,
there are 3 resistances, two capacitors in this circuit ,please tell me how to calculate each component value.

also tell me how to calculate led number acording to capacitance, and how to calculate capacitane according to voltage

please xplain with example, i am very eager to learn and i dont want to burn leds again :-).
thank you again sir for your concern

• Seetharaman
November 5, 2010

Hi Tony any size 3volt 50mA LEDs.

• tony
November 4, 2010

Hi Seetharaman,

This circuit suitable for 5mm or 10mm LED ? Thanks

• Seetharaman
November 3, 2010

Hi Tony you can use switched mode power supply available for 12 volt halogen lamps(they are available in various load ratings). you can use 4 hi bright white LEDs in series and connect it to SMPS through 5 ohms resistance in series with each group as currnet limitting resistance. each group requires 12 volt at 50mA. If you use 100 groups you require 60watt SMPS to take care of all these 400 LEDs. You can increase or decrease in the order of 4 LEDs group.

• tony
November 2, 2010

Hi Seetharaman,

Thank you Sir for your valuable information and if want to increase the LED from 24 nos to maybe 300 or 400 nos how to do it like what China manufacture sell it call LED Flood lamp?

• Seetharaman
November 1, 2010

Hi Tony this has been installed in Hotel Lounges and Rest rooms and they are working for the last 1 year without any problem. initially we had problem with 1N4007 MIC make(light will become dim and start flickering). and the electrolytic capacitor(which use to get ruptured). We have switched over to Philips and Keltron, since last one year no problem at all.
Hi Luis for 115volt 60Hz you replace 1uF 400 volt with 0.82 uF or use the same 1uF increase LEDs to 35 nos.
If you want to use one LED for just mains indication use a 4.7 K resistance 3 watts in series and a diode 1N4007 in reverse biased condition across LED. you can use 0.47uF for 1uF and use only 1LED all other components are same.

• tony
October 30, 2010

Hi Guys out there,

So far how many of you try this circuit and can last how long the LED’s, 6month or 5 years?

• Luis Zunico Zuñiga
October 29, 2010

Les agradeceria me indicaran como calcular los valores de los componentes para un suministro de Red de 115 V AC

• Seetharaman
October 21, 2010

Hi Japanjot you can use 2volt (1.7 volt at 20mA)red leds SAY YOU WANT TO USE 40NUMBERS then the voltage is 68 volt at 20mA. retain increase 100 ohms before bridge rectifier as 220 0hms and capacitor as 0.33uF (330nF)
For yellow and green (they are 2volt devices at 20mA)say for 35 LEDs 35 X 2 = 70 volts. the same modification will do.

• japanjot
October 20, 2010

what would be the changes to be made if i want to install red led of 2v each or yellow led of 2.2v each in this circuit insted of white 3.5v

• Seetharaman
October 19, 2010

Hi Japanjot these 28 to30mA LEDs are safe with 25mA hence in the above circuit you have to change 1uF 400 volt to 470nF 400 volt and 100 ohms resistance before bridge rectifier as 220ohms, other components kept un changed. for 60mA change 1uF to 1.2uF no other component requires change. the values are 230 volt 50Hz. use the formulae R = V / I AND f = 1 / 2pi R X C

• Rakesh
October 19, 2010

Seetharaman sir,
How can I measure its wattage, My Multimeter is a low profile one, it can only detect ac rms value of voltage and dc voltage and dc current.

• japanjot
October 19, 2010

one more thing, i checkd my leds , they are of 28 to 30 ma current each what to do?
any changes are to be made?

and can u tell me the changes to be made for total 60 ma output

really thanks alot

• japanjot
October 18, 2010

ok thnx sir,

1): what would be the value of frequency here would it be 50?, and
2):how you set the current in this circuit, i mean wts the formula for setting desired current like 30 ma, 50, 100, 150 ma etc
3):what would be the changes to be made if i want to install red led of 2v each or yellow led of 2.2v each in this circuit insted of white 3.5v…

thnk you sir, and would be eagerly waiting for your helping hand

• Rakesh
October 18, 2010

Seetharaman,
I’ve used 0.68 uF instead of 1uF for the mains supply and no resistance with it. Yet it worked, with little less brightness. There was 48 LED-s in series. I used a bridge rectifier package.
I will be happy if there is any brightness control, and what is the probable power consumption?

• Seetharaman
October 13, 2010

Sorry Japanjot. there was a mistake. it should be f = 1 / 2pi R C. f is frequency R resistance and C is capacitance

• japanjot
October 12, 2010

sir what is f and F in the formula

• Seetharaman
October 8, 2010

Hi Japanjot you can glow 60nos 50mA high bright white LEDs in the above circuit with 2uF capacitor.
The formula is f = 1 / 2 pi F C

March 25, 2014

Sir

Please Help to know how I can Calculate Current Flow of Power supply Output, and each Component Value (Rating), Also can i Connect LEDs in Parallel instead of Series to avoid circuit failure due to even one LED goes faulty, This can be achieve by Increasing Current and decreasing Voltage, Can you please help me to know calculation.

Also if LED rating is not mentioned on LEDs so how i can know its Current and voltage rating

Thanks

• japanjot
October 7, 2010

sir how many leds can glow with 2 uf cap? can u tell me the for mulas with which u calculate resistances and capacitance for this circuit.thank you again

• japanjot
October 7, 2010

October 6, 2010

Sir,

Its working fine. Thank you.

• SAJU
October 6, 2010

sir,

I have assembled the circuit and working fine. But The LEDs gets faded out within 2-3weeks time. Is there any thing wrong

• murali
October 6, 2010

thankyou sir

murali

• Seetharaman
October 6, 2010

Hi Murali nothing requires any change other than capacitor. For 0.82 you can use 680K and 100K in parallel. for 1.2k you can use 680k and 470k in prallel. a small difference in current will not matter much. With 680k and 19LEDs the current flow through leDs will be 48mA which is ok.
Hi Japanjot for 50 LEDs you replace 1uF with 1.5uF. for 100 LEDs use two circuits as above with 1.5uF capacitors

• murali
October 5, 2010

i connected 19 led with 680k capacitor its working will there be any problem or i have to change anything in d circuit

regards
murali

• murali
October 5, 2010

iam not able to get 0.82uf & 1.2uf capacitor a got only 220k, 470k, 680k, capacitor what should i do

• japanjot
October 5, 2010

sir was looking for project lyk yours for very long, sir what to change for 100 leds and 50 leds.

• Seetharaman
October 5, 2010

Hi Murali for 19 LEDs reduce capacitor to 0.82uF, a standard value or use a 15volt in series with th LED loop.
For 42 LEDs increase capacitor to 1.2uF you will get around 47mA current there will not be much of brightness reduction can be noticed.

• murali
October 4, 2010

i bought 2 led plastic housing but in that i can only fix 19 & 42 leds of 50ma what should i change in this circuit thanks for ur reply

regards
murali

• Seetharaman
October 1, 2010

Hi Sethumadhavan check the capacitor 10uF for a short. disconnect 10uF measure the pulslating DC with AC and DC content with a multimeter if it is ok replace the 10uF after connecting LED circuit energise it should work. you can use without 10uF also for a short duration during check. without this also LEDs will glow. this is used for switch on surge protection. finally connect it back. (check each LED seperately with 3 volt supply – use a lithium disc cell for fast checking)

September 30, 2010

Hello Sir,

I’ve noticed already before assembly and done it in right way.

• Seetharaman
September 30, 2010

Hi Sethumadhavan the above bridge circuit is wrong kindly rotate it by 90 deg. this may be the reason

September 30, 2010

Thank you Sir,

I’ve used bridge instead of 1N4007. The LED’s are not glowing. How I can trouble shoot it? I’ve disconnected the supply to the LEDs but not receiving any the voltage? Can you pl guide me?

Regards,

Sethu

• Seetharaman
September 30, 2010

Hi Sethumadhavan No load output voltage will be mains voltage X root 2. that is approximately 350volts DC. which will damage the capacitor instantly or if the capacitor is ok then the current limitting resistors 100 ohms will get burnt.

• murali
September 29, 2010

thank u sir for ur reply

• Seetharaman
September 29, 2010

Hi Murali you require to change only the 1uF capacitor.
For 15 LEDs it should be 0.77uF ( 2 1.5uF in series)and for 36 LEDs it should be 1.2uF

September 29, 2010

Dear Mr. Seetharaman,
What will be the no load o/p voltage and the current (disconnecting the LED) across 10µf / 100V capacitor?

• murali
September 29, 2010

thank u sir, i tried this 24 leds circuit today its working fine & very bright/ for 15led & 36 led of 50ma what should i change in this circuit. waiting for ur reply i once again thank u sir

• ravi
September 23, 2010

thankyou sir

• Seetharaman
September 23, 2010

Hi Ravi you want to use this circuit with the UPS of computer for the glow, yes you can go ahead

• ravi
September 22, 2010

Hi sir can I use this circuit for sinewave inverter those are used for computer.

• Seetharaman
September 21, 2010

Hi Patrick since all the LEDs are in series you require around 72 volt DC, hence we have to redesign the circuit to suit either 6 volt or 12 volt battery. i will keep in mind for the future project.

• Patrick Vaz
September 20, 2010

Hi Seetharaman,
This is a good circuit(transformer less) mains operated LED CIRCUIT. but just to take a step further if a Battery say 6v 4ah is added to make it mains operated LED with battery back up. would there be much changes required in the circuit.
Regards

• Seetharaman
September 20, 2010

Hi Ravi Sorry the bridge rectifier is drawn wrongly. please rotate it by 90deg.
Pl refer to my comment dated 26th june

• ravi
September 20, 2010

Good evening sir if Bridge connected as usual what happen’s, please suggest me

• Mouly
September 13, 2010

thanks Sir

• seetharaman
September 13, 2010

Hi Mouly with capacitance in circuit it is +0.3 hence you have to add inductance also. this will become bulky. to avoid that you can shift to switched mode power supply then you can achieve almost unity power factor but the circuit will become expensive.

• Mouly
September 13, 2010

Can the power factor of this circuit be around 0.9.how to improve power factor of this circuit.In simulation the power factor of above circuit is just 0.3 .how to make it 0.9

• seetharaman
September 13, 2010

Being a capacitive load power factor will be positive and quite low in value. The power measured was so low and hardly 3watts.

• Mouly
September 13, 2010

What is the power factor for this circuit Sir.What is the best power factor in case of AC to DC conversion circuits without using transformers.Please explain me about power factor.Waiting for reply

• seetharaman
August 4, 2010

Hi KVS, Please refer my reply on 26th june on correction to bridge rectifier it should be rorated be 90 deg clockwise. you may please go ahead it will work nicely. See my prototype units photographs.

• August 3, 2010

is this circuit is correct? in the bridge side sir? the input ac supply is connected to anode and cathode point of the bridge circuit in other circuits.

please tell me sir. i’m bought the all components and assembled. but finally i check the circuit, i got this doubt.

• mouly
July 19, 2010

• Seetharaman
July 19, 2010

It is the peak charge current limitation for the capacitor. wihtout this it’s internal resistance will be zero initially hence the initial charging current will become infinite exploding the capacitor instantly. refer capacitor manufacturers catalog for the recommended max current.

• mouly
July 19, 2010

what is the formula to calculate the resistor to limit the peak charging current

• Seetharaman
July 19, 2010

Hi Mouly it is to limit the peak charging current to well within 2Amps

• mouly
July 19, 2010

How to calculate that resistor (100 ohms) value.Waiting for reply

• mouly
July 19, 2010

Thanks for your response sir why is another resistor is connected to other end of 23o volts(100 ohms).waiting for reply

• Seetharaman
July 19, 2010

Hi Mouly use the standard formula f = 1 / 2 pi r c. Discharging resistance must be capable of discharging the capacitor in few seconds.
1F will give 1A for 1sec.

• mouly
July 19, 2010

Sir,
How to calculate the value of the ploy capacitor for the above circuit like wise the resistor value in parallel to it.Waiting for reply Sir

• seetharaman
July 15, 2010

Hi Ganesh
Hope you require this for 120Volt 60Hz then the only change is increase 1uF 400volt to 3.3uF 250 volts even 400 volts can be used. All other components are same

• Ganesh B V
July 13, 2010

Sir,
How to use this circuit for 120 v power supply?

Thanks

Ganesh

• mouly
June 28, 2010

Thank you Sir

• rakesh
June 28, 2010

thanks for ac led circuits

• seetharaman
June 27, 2010

Hi Mouly If the LED strips are for 25mA, then you can connect two in parallel. if it is for 50mA each then you have to double the input capacitor to 2uF.

• mouly
June 27, 2010

Thank you for you response sir.Can I connect two parallel led strips each with 24 leds if so should I change any components.waiting for reply

• seetharaman
June 26, 2010

Hi Mouly 470K to discharge the 1uF capacitor after switch off. The resistances are for limitting the in rush current due to the 1uF capacitor. Since the circuit is for 50mA LED 100 ohms 1/4 watt is required, as the light is enclosed a 1/2 watts resistance to be used. 1uF capacitor is calculated from the Xc required for the current required and the voltage drop required. the 10uF capacitor is for to get a slow raise of voltage and current to LEDs to protect then as they are in series.

• mouly
June 26, 2010

Very nice circuit sir .How to calculate the components vaules.What is the use of 470k ,how to calculate similarly other two resistors.please let me know.waiting for reply

• seetharaman
June 26, 2010

Hi friends there was an some doubts about the circuit. Please note.
. 50mA is the current through the circuit. That is 0.05 X 0.05 X100 That is 0.25 watts hence 1/2 watt will do. similarly for 470K 0.25 watts will do.

With the capacitor value shown the limitation is 24 LEDs.

In the place of bridge 400C1 bridge you can use 4 nos 1N4007 since its PIV is 1000volt.

Minimum PIV required is 600volts.

The 100 ohms resistances used are for surge limitting
470K to discharge the capacitor and the 10uF in the DC to protect during initial surge current. All the components used have purpose plese donot delete any you may loose your valuble LEDs on the long run.

• deepak
June 26, 2010

why are all the LED’s connected in series..the voltage across each of them will not be the same…isn’t it better to connect all the LED’s in parallel with an appropriate resistor so that all LED’s have the same voltage across them..

• June 25, 2010