Easy 1 Watt LED Driver Working with 220V/120V AC

White LEDs are the lighting solutions of the future, simply because these devices can be lit brightly at relatively negligible power consumption. As an example, 1 watt LEDs are getting very popular nowadays due to their mini size and intense point brightness outputs, and as usual these require just  a watt at 4 volts for generating dazzling illuminations.

Overview

In this article I will show you how to build a very simply 220 V or 110 V operated 1 watt LED driver circuit,that would cost you not more 1/2 a dollar, excluding the LED of course.
I have already discussed capacitive type of power supply in a couple posts, like in LED tube light circuit and in a transformerless power supply circuit, the present circuit also utilizes the same concept for driving the proposed 1 watt LED.

Simulation and Working

In the circuit diagram we see a very simple capacitive power supply circuit for driving a 1 watt LED, which may be understood with the following points.

The 1uF/400V capacitor at the input forms the heart of the circuit and functions as the main current limiter component of the circuit. The current limiting function makes sure that the voltage applied to the LED never exceeds the required safe level.

However high voltage capacitors have one serious issue, these do not restrict or are not able to inhibit the initial switch ON mains power in rush, which can be fatal for any electronic circuit LEDs are no exceptions.
Adding a 56 Ohm resistor at the input helps to introduce some damage control measures, but still it alone cannot do the complete safeguarding of the involved electronics.

An MOV would certainly do, also what about a thermistor? Yep, a thermistor would also be a welcome proposition.
But these are relatively at the costlier side and we are discussing a cheap version for the proposed design, so we would want to exclude anything that would cross a dollar mark as far as the total cost goes.

So I thought of an innovative way of replacing an MOV with an ordinary, cheap alternative.

What is the function of an MOV


It's to sink the initial burst of high voltage/current to ground such that it is ground before reaching the LED in this case.

Wouldn't a high voltage capacitor do the same function if connected across the LED itself. Yes it would surely operate the same way as an MOV.

The figure shows the insertion of another high voltage capacitor directly across the LED,  which sucks the instantaneous influx of voltage surge during power switch ON, it does this while charging up and thus sinks almost the entire initial voltage in rush making all the doubts associated with a capacitive type of power supply distinctly clear.

The end result as shown in the figure is a clean, safe, simple and a low cost 1 watt LED driver circuit, which can be built right at home by any eletronic hobbyist and used for personal pleasures and utility.

CAUTION: THE CIRCUIT SHOWN BELOW IS NOT ISOLATED FROM THE AC MAINS, THEREFORE IS EXTREMELY DANGEROUS TO TOUCH IN POWERED POSITION.

 Circuit Diagram


simple 1 watt led driver circuit


In the above shown simple 1 watt led driver circuit, the two 4.7uF/250 capacitors along with the 10 ohm resistors form a kind of "speed breaker" in the circuit, this approach helps to arrest the initial switch ON surge inrush which in turn helps to safeguard the LED from getting damaged.

This feature can be replaced with an NTC which are popular for their surge suppressing features.

This enhanced way of tackling the initial surge inrush problem could be by connecting an NTC thermistor in series with the circuit or the load.

Please check out the following link for knowing how to incorporate an NTC thermister in the proposed 1 watt LED driver circuit

The above circuit can be modified in the following manner, however the light may be a little compromised.

A good way of tackling the initial surge inrush problem is by connecting an NTC thermistor in series with the circuit or the load.

Please check out the following link for knowing how to incorporate an NTC thermister in the proposed 1 watt LED driver circuit

https://www.homemadecircuitsprojects.com/2013/02/using-ntc-thermistor-as-surge-suppressor.html

 Prototype Images



simple 1 watt led prototype testing



transfomerless 1 watt led driver circuit using capacitor




1 watt led driver tested practical sample





The above circuit can be modified in the following manner, however the light may be a little compromised.


diode stabilized 1 watt capacitive 1 watt led driver circuit

Using a 6V Battery


As can be seen in the diagram, the concept hardly utilizes any circuit or rather does not incorporate any hi-end active component for the required implementation of driving a 1 watt LED.

The only active devices that's been employed in the proposed simplest 1 watt LED driver circuit are a few diodes and a mechanical switch.

The initial 6 volts from a charged battery is dropped to the required 3.5 volts limit by keeping all the diodes in series or in the path of the LED supply voltage.

Since each diode drops 0.6 volts across it, all four together allow only 3.5 volts to reach the LED, lighting it safely, yet brightly.

As the illumination of the LED drops, each diode is bypassed subsequently using the switch, to restore the brightness of the LED.

The use of the diodes for dropping the voltage level across the LEDs makes sure that the procedure does not dissipate any heat and therefore becomes very efficient in comparison to a resistor, which would have otherwise dissipated a lot of heat in the process.

driving 1 watt led with a 6V battery


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Comments

Swagatam said…
CFL bubs are very complicated to build because they involve inductors which are too critical...so i am sorry, no ideas.
Shaun P said…
Hello Swagatam!
Thank you for all of your time answering everyone's questions. I would like to use your circuit design in a middle school project to create LED light fixtures housed in home cut and planed cherry wood housings. I am wondering which of your two posted designs you would recommend for this project, and how many 1 watt LED's you think would be appropriate for a 3 foot long bar type fixture to give an impression of consistent lighting when used as uplighting mounted above eye level on a wall (I am imaging a simple V design for the housing).

Thank You!
Swagatam said…
Hello Shaun,

34nos 1 watt LEDs would be enough within a 3ft span. Remember that you will need a heatsink back PCB for mounting the LEds and an additional thick aluminum heatsink attached behind the PCB for optimum cooling.

Along with this you will have to incorporate a current limiter circuit with each LED module, and the the whole thing will need to be powered through a 2amp 12V smps.

For wiring details and calculations you may refer to the following post:

https://homemade-circuits.com/2013/02/make-this-1000-watt-led-flood-light.html
Andre S. said…
Dear Sir, i am no expert like you..


i want to try build a led driver.

the DC output should be

14 Ampere (60 * 700mA) , 168 volt (2,8 * 60) , 60 Watt (60 pc * 1 W)

since i want use 1 W led, DC2.3-2.8V 700mA each (read it on the spec of the bulb)..

i want to use 60 piece bulb of 1w power led.


is the DC out that i calculate is right or wrong ?
Swagatam said…
Dear Andre,

You can use the circuit which is given in the above article, by connecting all the LEds in series to the output. Be sure to connect a thermistor in series with the input of the above transformerless power supply and increase the input capacitor value to 5uF/400V non-polar

Your current calculation needs correction.....when LEDs are connected in series the current gets shared, meaning in your case the current would be just 700mA.....
By the way 1 watt LEDs are rated at 350mA not 700mA, I am doubtful about your specs.
Vivek Kumar said…
Sir

when i have made this circuit i got only 2.82 volt on each 1 Watt led.. so pls help me how to increase volt to 3.3V...
I have used following items...
1. 105K/400volt capacitor
2. 150 or 570K resistance for cap
3. 4 diode 4007
4. 56 ohm resistance 2 watt
5. 100V/100mf condenser
6. 1watt 3LED in series
Swagatam said…
Hi Vivek,

Increasing current won't be a good idea and is not recommended for such power supplies, instead you can use ordinary 5mm LEDs and connect 50 of them in series, it will produce much higher illumination than a three 1 watt LEDs.
Tanay Makwana said…
hi!
when I made the above ckt the resistor 56 ohms just gets blows and if it doesn't, the LED lights up but with very low brightness
Swagatam said…
please make this circuit:

2.bp.blogspot.com/-nKF8T8lKIxY/UMg7YDLNQ3I/AAAAAAAAB8U/S1OWTK0cMD4/s1600/Surge%20free%20transformerless%201%20watt%20LED%20driver%20circuit.png

Use 6 diodes and not 12, if you are connecting 1 LEd only
Swagatam said…
The above power supply will not be able to illuminate 1 watt LEDs even after suitable changes.
Swagatam said…
...i mean it won't drive with full illumination, anyway you can try connecting the LEDs in series with the above circuit and see the results.
Can you please provide me any link, or provide me some hint to understand how did you arrive at the input side capacitor of 1uF/400V? I mean how does this value of capacitor restrict or limit the current that is being used by power-led? Also how are we restricting the voltage supplied to the led to 3.4V. I know that even if we provide 5V to the led the forward drop will always be 3.4V; but still if we provide a higher voltage maybe something like 200Vdc then I believe the led will burn out. Then how do we limit the voltage supplied to the led?
Swagatam said…
The current is important here which we want to limit by putting a resistance in series with the mains, the capacitor acts like a resistance here which is calculated by calculating its reactance, you can Google a little to find the formula for reactance, this will be in Ohms, next you can employ Ohms law to calculate the current that can be limited through this reactance or resistance.
Swagatam said…
The voltage gets automatically restricted to load voltage only in case the current is considerably lower than the maximum spec of the load (LED here), since a 1uF/400V can allow a max of 70mA which is far less than the 1watt LEDs 350mA, the voltage settles down to the LED FWD V level
Swagatam said…
If it's 20mm type then yes you can use it with full capacity
Swagatam said…
......sorry i meant 20mA
Swagatam said…
Hi, What is your driver voltage?

You will need to put appropriately calculated resistors with each ED, only then all will light up with uniform brightness.
masoud said…
Hi output voltage of about 3 volts. Is it possible to add., And because the filter capacitor should be 250 volts.
parthiban said…
dear mr.Swagatam,

i need transformerless LED driver for 3Watt LED
Wajed Pasha said…
Hi sir I'm planing to connect 40 1 watt led's in series so i want to add an fan speed controller for dimming. I'm interested in electronic but i don have much knowledge in electronic plese help me can u send me the pic of ready circuit for reference wajedpasha58@gmail I'm waiting for Ur reply
Swagatam said…
Hi Wajed,

please refer to the last diagram in this article, you can try this for your project:

https://homemade-circuits.com/2012/11/using-fan-dimmer-for-controlling-led.html
Swagatam said…
Dear Muhammad,

You will have to measure the volts across the leads of the LED, and measure current in series with the LED, then multiply the results to get the wattage.
which type of capacitor used at input & output stage for above circuit please tell. as early as possible
Swagatam said…
input is metallized polyester, and output can be a metallized polyester or an electrolytic
Virendra singh said…
how to lighten up 20 LED of one watt each connected in parallel , n how many voltage require i have a 35voltage DC battery and how to control upcoming voltage from battery to glow much brighter
Swagatam said…
with 35V you get an opportunity to connect 10 LEDs in series with a single limiting resistor, so with 20 LEDs you can make two such strings and connect them in parallel.

The resistor value will be 6 Ohm 1 watt for each string.

The above set up will produce the most optimal response from the LEDs
is there any circuit to glow 10w single chip led from 230v main?
Swagatam said…
an smps is the only solution, no other easier method.
Can i use J3305 transistor sir?
hanumanth said…
Hello Sir,

I have seen your posting of 1watt led drive from mains supply its good i have tried but,
my led has blown out and i have checked the out put is showing 320v Dc..
I have used the the below parts..
1) 1N4007
2) Resistor 1mego ohm 1/4watts
3) Resistor 56ohms 1watt..
4) capacitor 105/400v polyster type.
5) Capacitor 104/250v polyster type.
6) LED 1watt white.
I have connected as per the draw shown above kinldy le me know where im doing the mistake..
mains voltage i have given 240volts to the above circuit..
Kindly help me sir...
Hanumanth
Swagatam said…
replace 104/250 with 10uF/250V, or alternatively you can add an NTC as suggested in the following article.

https://homemade-circuits.com/2013/02/using-ntc-resistor-as-surge-suppressor.html
Hello I like your post very much keep it up!!!
Can I connect about 50 ,5mm leds to this circuit without big 1W leds??
Swagatam said…
hi thanks!
yes you can connect them...put them all in series.
use 474/400V instead of 105/400V
Saeed Abu said…
Bro how can i drive multicolor 3/4 LED by 220v through resistance only? it will be used as night lamp.
Swagatam said…
use a 2k/20 watt resistor
Abid Ginwala said…
Hi, Can you guide me with making of LED Street light using 30 Nos. 1W SMD LEDs connected in 3 rows in parallel with 10 LED's in Series. I will use available ready-made good LED Driver (pls give spec of Driver required). Thanx
Swagatam said…
Hi You'll need a 33V, 350mA SMPS driver circuit, preferably a current controlled type, if it's not current controlled you could employ the first design from the following link, in conjunction with it.

https://homemade-circuits.com/2013/06/universal-high-watt-led-current-limiter.html

Naresh S said…
Hi Sir,

What is the output voltage and current of the circuit?

Thanks,
Naresh.S
Swagatam said…
Hi Naresh, It would settle down to the 100uF capacitor voltage rating without load. and when a load is connected such as an LED it would further come down to 3.3V
Hemant Rajput said…

PLEASE help me i need 12-17 voltage circuit and minimum 0.5 ampere current and i only want to use maximum of 2 reistance and two capacitor and one bridge rectifire like in the circuit i mentioned in link.I just want to know the value of resistance and capacitance for my purpose
cdn.instructables.com/FZG/3MTW/G3KY0MRL/FZG3MTWG3KY0MRL.LARGE.jpg
Swagatam said…
Sorry that's not possible, you will have to include a transistor stage also for reliability and safety because at 0.5amps the initial surge will be too high which could damage the load instantly.
aravind said…
hai sir,
i am aravind
while i am surfing through internet i found that 1uf cap will provide 40ma.
then how it glows 1 watt led which requires 300ma.
does 40ma amp is enough?
please explain.
Swagatam said…
Hi Aravind, 1uF will produce 70mA not 40mA, but anyway the LEDs will not get 300mA from it and will light up with 70mA brightness only.
mahendiran T.V said…
dear sir,
Can i replace 1uf/400V by 220nF/400V or 1uf/250V
Swagatam said…
1uF/250V can be tried
Naresh S said…
sir shall i use 105k/250v instead of 1uf /400v?
Swagatam said…
It can be used but it won't be reliable....
Kimaya Samarth said…
hello,
Can you suggest a circuit to reduce the flickering of LED which is powered by energy generated from a small turbine rotated by water.approx voltage across LED is 1.6v
Swagatam said…
just connect a 100uF/25V capacitor directly across the LED leads.
Bambang said…
Hi Swagatam, i like your blog. i have question related changing "2pcs of 4,7uf/250v and 2 pcs of 10 ohm/1watt with 1 pcs of NTC. what value of NTC of it? is it 20 ohm?
Swagatam said…
Hi Bambang, it can be a 5 ohm NTC as shown in the following article:

https://homemade-circuits.com/2013/02/using-ntc-resistor-as-surge-suppressor.html
NJ said…
Hello Swagatam,

i have followed ur ckt . i want to connect the 18 LED having voltage 3.2V Current 150mA . i have used the 105J 400V capacitor . on AC side the current consumption is 70mA while on DC side at led it is 55mA only . I want to insincere the DC current at led side up to 130mA and decrease the AC current up to 30mA.

Kindly suggest mi how to do that
Swagatam said…
Hello NJ, that's not possible with a capacitor power supply because the input/output stages are not isolated.
James Franco said…
I tried to add inductor (2.4mF), but it does not higher PF. Did you find any solution for improving PF?
sir, i want to make this circuit with 10 * 1W leds in 230v
how can do it?
Swagatam said…
Janith, simply connect them in series with the shown circuit....that' all, if possible connect a coil in series with the LEDs as indicated in the following article:

https://homemade-circuits.com/2015/05/make-1-watt-led-lamp-using-20ma-leds.html

sat said…
IN 4007 diode is rated for 1000v - 1A. connecting 50 x1w leds would put 5000mA (100mA per 1W led) through the DIODE Bridge.. Pl explain how can it work?
Swagatam said…
series connection does not call for current multiplication, rather it involves voltage multiplication....so for 50 LEDs in series current requirement will be 100mA....but voltage requirement could be approximately 50 x 3.3 = 165V
Dear sir,
this is Shrinivas from Amravati.
How can be modified this circuit to draw 20mA (for single 5mm LED)? Coz I've tried single 5mm for this circuit bt it lits very brightly which is resulting high temp & no durability. So please suggest exact value (for R?)
Thank you so much sir.
Swagatam said…
Dear Srinivas, replace the input 105/400V capacitor with a 0.33uF/400V capacitor
Dear sir,
I want to attach it a single 5 mm led to project its beam on the wall clock.
So how can be modified this circuit for a single 5mm led? (enough brightness which shouldn't harm led's durability)
Thank you so much sir.
Swagatam said…
use a 0.33uF/400V capacitor in place of the shown 105/400V cap, you can try a 0.22uF/400 first if it does not give sufficient light then go for the 0.33uF/400V option
fidel catsro said…
dear Swagatham, in reference to the simple single diode schematic diagram : can I replace the 1megaohm resistor in parallel to the 105uf 400v ac capacitor with a neon bulb instead? the 1 megaohm resistor is a simple discharge mechanism to prevent the cap from keeping its current in it and causing a shock when touched accidentally etc whilst being removed from the ac outlet right?
Swagatam said…
dear fidel,

you can use a neon bulb in series with the 1M resistor.....but you cannot replace it

that's right, it's for discharging the dangerous mains potential when the circuit is unplugged
kamlesh_sexy said…
Hi friend,
How are you? hope u doing gr8, I am again in little confucsed with led current value, i mean i went to market few days ago to buy 50nos 1w led, but in one shop i got only 20nos and another shop i got 30, so i got total 50nos. Ok after taht i came to home and connect led's to desire voltage (output voltage of battery is 3.2v) the 20nos of led (from 1st shop) brightness is ok, but another 30nos led (from 2nd shop) brightness is different, my question is how to know led current value, i mean 350ma or 300ma? is there any calulation method or any way to check the led current????
Thank you....
Swagatam said…
Hi friend, I don't think there's any testing equipment or method which will identify the wattage of an unknown LED??

but in your case it's just because of difference in quality or color spec....both could be 1 watt/350mA but due to different brand, the illumination could be slightly different.
Baron Joe said…
Sir!
Can this be modify to detect overvoltage, a spike or a transient
in the mains? Light up the led, and way not log it with an ARDUINO ;-)
Tank's, Joe.
Swagatam said…
Baron, the over voltage can be simply stabilized by putting a zener diode across the LED terminals, and the spike or transient can be controlled by inserting an NTC thermistor alone or in conjunction with an MOV ;-)
Aneil Khadgi said…
Hello Sir . can i used 12v 1amp adapter to 10 watt led
Naresh S said…
Hey sir

What if i use 1uf 650 v ppc instead of 400v?
Naresh S said…
And which circuit is safety first one or the second one?
Swagatam said…
naresh, yes it will do...
Swagatam said…
second one but light will be less.
kamlesh_sexy said…
Hi friend,
I liked 2nd diagram, but I don't have 10uf 250v capacitor at the moment, currently I have:
10uf in 16v, 25v, 50v, 63v.
so what capacitor voltage I can use instead of 10uf 250v??? please suggest me.
Swagatam said…
Hi friend, you can try 100uF/25V instead, just connect a 12V zener in parallel with the vertical 1N4007 diode
wonderful work you are doing here.
more power to your elbow sir.
Swagatam said…
you are most welcome Madamidola
prithipal singh said…
Hello swagatam ji
4.7 mfd 250v is electrolytic capacitors
Flavio Soprano said…
Luego de casi un lustro llega a Sur América problemas para resolver tecnolócamente que ud mi estimado amigo ha resuelto y compartido... gracias... hacía hace un tiempo este circuito para leds de 60mW y me preguntaba si funcionaría con chups de 1w. Saludos y gracias.

After almost five years come to South America to solve problems you my dear friend and shared resolved ... thanks ... some time ago this circuit 60mW LEDs and wondered if it would work with chups 1w. Greetings and thanks.
Swagatam said…
thanks very much, Im glad to know this!
fidel catsro said…
hi Mr Swagatam, I would like to make a single on /off button switch circuit that controls 2 different paths to switch 2 different appliances at each on/off button, means first press ON it switches on a lightbulb A, press button again it switches OFF light A, press same button again, it will switch lightbulb B, press same button it turns off, press again it comes back to light A,and so on..
Swagatam said…
Hi Mr. Fidel you can use the following design, but you will need to skip one pinout of the IC between each sequence, in the diagram the sequence is continuous, which will need to be changed:

https://homemade-circuits.com/2013/08/single-push-10-step-selector-switch.html

Jony Hossain said…
sir I want to build a circuit without transformerless power supply for eight led 4-4 series and two series are parallel,
but I can't build this circuit. Please help me
Swagatam said…
..without transformerless power supply??? sorry that may not be possible because connecting LEDs directly to mains will blow them up
Unknown said…
Hi Swagatam,
I have been following your blog for quite some time.Its a very good blog and I have made many circuits by following your circuits. I wanted to make led street lights but the frames i have are the old types you know those 40 watts one. So can you tell me how to make them like the circuit and what type of led's can be used to have bright white light.
Swagatam said…
Hi, thanks, the power will depend on your choice and the source of power.

the frame or the fixture can be only used as the base, the wiring won't be of much use, however you could refer to the following circuit and possibly modify your 40 watt strips accordingly

https://homemade-circuits.com/2014/06/led-tube-light-circuit-which-will-fit.html
Blog has been removed

Sorry, the blog at homemadecircuitsandschematics.blogspot.com has been removed. This address is not available for new blogs.
hello swagatam sir,
in the first circuit ,instead of 4.7uf,250v can i use 10 uf,250v.
If i make first circuit as it is ,then also NTC is necessary?
regards
aabhishek sharma
Swagatam said…
Hello Abhishek,

you can use 10uF/250V, however if a single NTC is used then these big capacitors can be eliminated
Hi sir, I made circuit and actually was working perfectly but after 2 minutes the third capacitor 100uf 63v got burst, I was using only one red colour led (normal) everything else is same.
Should I might also consider checking diodes before restarting the circuit after repair.
Swagatam said…
Yes, make sure all the parts along with the 1N4007 diodes are original, and of good quality.

use a 12V / 1 watt zener across the output +/- lines, this will prevent the capacitor from getting damaged.

remember this circuit is for 1 watt LED, NOT for 20mA LED, if you want to use 20mA LED then replace the 105/400V capacitor with a 0.22uF/400V capacitor.

please don't do anything without understanding
Rajagilse said…
Sir, what alterations should I do if put 5 watt single led in place of 1 watt?
Swagatam said…
Raja, 5 watt cannot be used in the above circuit, you can try the following circuit instead

https://homemade-circuits.com/2016/07/scr-shunt-for-protecting-capacitive-led.html
Rajagilse said…
Sir, could I put NTC in place of so many diodes in the under mentioned circuit, then will it become surge proof ? could I put about 15 no. of 1 watt LED for that ? Is there any alteration needed ?

2.bp.blogspot.com/-nKF8T8lKIxY/UMg7YDLNQ3I/AAAAAAAAB8U/S1OWTK0cMD4/s1600/Surge%20free%20transformerless%201%20watt%20LED%20driver%20circuit.png
Swagatam said…
Raja, yes that's possible but NTC will need to be placed in series with the supply, not at the points where diodes are connected.

it will prevent surge but it will not stabilize the voltage, and it is recommended only for initial switch ON current control not for round the clock control

15 no LED can be used, but should be in series
Charan said…
Hi Swagatam, i tried the basic transformerless circuit from u r previous posts and ive used single 1 watt led but resistor started heating up. I am using 474k/400v cap and single led (1 Watt) . since there r many ckts in ur site which uses 1uF cap suggest me a ckt suitable for me....
Swagatam said…
Hi Charan, you can remove all the resistors and just use a single 100uF/50V capacitor, but make sure to add a 6V 1 watt zener diode after the bridge rectifier, and yes you can use a 1uF/400V instead of 474 for greater brightness.

for full brightness you can incorporate the following concept, but again make sure to replace the zener diode with a 6V zener

https://homemade-circuits.com/2016/07/scr-shunt-for-protecting-capacitive-led.html

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