Skip to main content

Simple LED Tubelight - Explained Comprehensively

Explained in a very lucid style and through a schematic the complete construction of a LED light tube circuit which can be operated directly from the 230V AC mains of your domestic supply. This will not only save electric power but also help curb the global warming issue.

Transformerless LED Tubelight for Power Saving


The simple construction of an LED light tube discussed here will not only save electric power but also if used in every house will help reduce the ever increasing global warming effects.


Transformerless LED tubelight circuit with MOV protection



Today we are all aware regarding the bad effects of global warming and how it’s gripping our only planet day after day. But for this we ourselves are to be blamed.

You may be thinking how a common person can contribute to help solve the problem. Well look around you, yeah, it’s the lights that we are using presently generate quite an appreciable amount of heat to add to the global warming effect.

CFLs are considered to be quite efficient, but they too release quite a bit of heat. The issue can be very easily solved simply by transforming our heat producing lights into the "cool" white LED lights. We will learn in this article how simple it is to build a LED light tube that can easily replace your existing "hot" fluorescent tube lights!

LED tubelight with zener diode protection


You will require the following Parts for the construction:

One 36 inches long, 2 inches in diameter white PVC pipe,
150 Nos. White LEDs (5mm),
4 nos. 1N4007 diodes,
3 nos. 100 Ohms resistors,
1no. 1M resistor, 1/4 W,
1no. Capacitor 105/400V, Polyester,
14/36 Wire for connections,
Soldering iron, solder wire etc.

How to Build a Homemade LED Tubelight Circuit


The construction of this circuit is carried out through the following simple procedures:

Cut the PVC pipe lengthwise into half.

Drill equally distributed LED size holes over the entire area of the two halves of PVC pipes. As shown in the diagrams just fix all the LEDS throughout the pipe.
Be sure to keep the position of the polarity of all the LEDs in the same orientation, Cut and bend the LED leads so that the leads touch each other side by side.

Make 3 series of 50 LEDS each by soldering the joints.

Make sure that each series comprises the given resistor of 470 Ohms.
Connect the 3 series LEDs groups in parallel by joining their positive and negative leads together through flexible wires.
Make a bridge configuration rectifier by joining the 4 diodes together, and connect the relevant points to the LEDs and to a 2 pin mains cord, as shown in the figure.

 How to Test it?


Testing this LED tube light circuit is probably the simplest part of the whole operation; it is done through the following simple steps:

After finishing the construction procedure as described above, just plug in the 2 pin plug into the mains socket (be extremely careful as the whole circuit may contain leakage currents).

Instantly all the LEDS should come ON giving a dazzling effect. If any of the series is dead or not glowing, switch OFF the power and check for the LEDs connected with wrong polarity.

Glue all the LEDs so that they may not come out of the holes I which they are inserted. Finally join the two halves of the PVC pipes with the LEDS, either by tying them or gluing them together with cynoacralite bond. Close the two open ends of the tube appropriately.

This concludes the construction of the LED light tube circuit. For optimum performance it would better to hang the unit from the ceiling so that the light is distributed equally.

The PCB Design Layout for the above LED tube-light circuit can be seen in the following image.

complete PCB design for transformerless tube


Video Clip showing the testing of a similar LED tubelight using 108 LED in series parallel combination


Below is a 50 LED Tube Light made by Merley, for your viewing pleasure:

built prototype image of the tubelight


LED string light made by Mr.Bibin Edmond using the explained capacitive power supply.

led tubelight using red lights


Here's the image of the simple capacitive PS circuit used for lighting the above string LED light.....

courtesy: Bibin Edmond


high voltage capacitor with bridge rectifier


In case you think that a transformerless based LED tubelight may not be reliable or not powerful enough, you can opt for a transformer based power supply design for accomplishing the same, as described below.

LED Tube light using a Transformer Based Power Supply


In the following sections we will see how to make a simple lED tubelight using a transformer based power supply, and by connecting the desired number of LEDs in series parallel connection.

Using white LEDs for illuminating our homes is becoming popular nowadays, due to the high power efficiency involved with these devices.

The diagram shows a straightforward configuration involving many LEDs, arranged in series and parallel.

Circuits Description


Referring to the shown LED tube light circuit using transformer we see the LEDs are driven by a general purpose 24 V power supply for illuminating the LED bank very brightly.

The  power supply incorporates standard bridge and capacitor network for the required rectification and filtration of the supply voltage to the LEDs.The arrangement of the LEDs is done in the following way:

The supply voltage being 24, dividing it by the forward voltage of a white LED which is around 3 volts gives 24/3 = 6, meaning the supply voltage will be able to support at the most 6 LEDs in series.

However since we are interested to include many LEDs (132 here), we need to connect many of these series connected strings of LED through parallel connections.

That's exactly what we do here.

Total 22 strings of LEDs having 6 in each are connected in parallel, as shown in the figure.

Since current limiting becomes an important issue with the white LEDs, a limiting resistor is added in series with  each of the strings. The value of the resistor may be optimized by the user for adjusting the overall illumination of the LED tube light.

The proposed design will provide enough light for illuminating a small 10 by 10 room brightly, and will consume not more than 0.02 * 22 = 0.44 Amps or 0.44 * 24 = 10.56 watts of power.

24 Volt, LED Tube Light Circuit Using Transformer, Circuit Diagram


In the above designs we have learned how to make LED tube light without any current control which may be OK if the LEDs are not power LEDs and do not have the property of getting too hot due the extremely high bright illumination.

However for power LEDs which are designed to emit extremely high bright lights and which have the tendency to become too warm quickly, a heatsink and a current control feature become very important.

Why Current Controlled is Crucial for LEDs


Current control in an LED tube light becomes crucial because LEDs are current sensitive devices and can quickly get into a thermal runaway situation, ultimately damaging it permanently.

In an LED thermal runaway situation the LED starts drawing more current, and begins getting warmer due to the absence of a current control limit. The rising heat inside the LED fores the LED to draw even more current, which in turn cause more heat, this goes on until the LED is completely burnt and destryed. This phenomenon is known as thermal runaway situation in an LED.

To avoid this current control becomes too crucial for any LED driver circuit.

In this circuit resistor R2 is placed for converting the rising current to voltage across itself.

This voltage is sensed by R2 which immediately conducts and grounds T1's base rendering it inactive, the instantaneous process initiates a switching effect, producing the desired current control and safeguarding of the LEDs.

Each channel consists of 50 white LEDs in series. R2 is calculated with the following formula: R = 0.7 / I, where I = Total safe current consumed by the LEDs.The whole circuit of the current controlled LED tube light may be understood in this manner:

Simulation and Working


When input AC is applied to the circuit, C1 drops the input current down to a lower level which can be considered to be safe for operating the involved electronic circuit.

The diodes rectify the low current AC and feeds to the next current sensing stage consisting of T1 and T2.

Initially T1 is biased through R1 and conducts fully illuminating the entire array of LEDs.

As long as the current delivered by T1 or rather current drawn by the LEDs is within the specified safe limit, T2 remains in a non-conducting state, however of the current drawn by the LEDs begins to cross the safe limit, the voltage across the limiting resistor R2 begins to develop a small voltage across it.

When this voltage exceeds 0.6, T2 begins to leak through its collector emitter pin outs.
Since the collector of T2 is connected to the base of T1, the biasing current to T1 now starts leaking to ground.

This inhibits T1 from conducting fully and its collector current stops rising any further. Since the LEDs form the collector load of T1, the current through the LEDs also gets restricted and the devices are safeguarded from the rising current intake.

Ths above rise in the current takes place when the input AC rises, producing an equivalent increase in the LED current consumption, but the inclusion of T1 and T2, ensures that anything that's dangerous to the LEDs is effectively controlled and curbed.

Parts List for the proposed current controlled LED tube light circuit

T1 and T2 = KST42
R1, R2 = To be calculated.
R3 = 1 M, 1/4 W
Diodes = 1N4007,
C1 = 2 uF / 400 V,



current controlled LED tube light circuit




Need Help? Please leave a comment, I'll get back soon with a reply!




Comments

  1. hello sir i want to know what mov value ??? bcz here not available zener diode plz plz plz reply my question ???

    ReplyDelete
  2. Hello Asad,

    You can try this one: MOV-14D471K or simply a thermister will also do, you can try this one:

    https://homemade-circuits.com/2013/02/using-ntc-resistor-as-surge-suppressor.html

    ReplyDelete
  3. Hi Swagatam Sir,
    Can i use a 3 zener diode in place of the 200v zener diode b'cuz 200v zener diode is not available near my house. If not please tell what i should do instead?

    ReplyDelete
  4. Hi Arpan, 3V zener will not work, you can try an NTC thermister instead, as shown in this article:

    https://homemade-circuits.com/2013/02/using-ntc-resistor-as-surge-suppressor.html

    ReplyDelete
  5. 90 to100 LED
    2amp 12V DC suplay input $$$$
    pls tell the resister specificaton with details????

    ReplyDelete
  6. Hi Swagatam,
    I am saty, back again
    1.accoring to the 3rd circuit (150 led circuit) how to connect 12v/7AH battery pls let me know the changes of components or as represeted in the diagram.
    2.150 Leds over load protection is there am i right. Please let me,know
    2. overload protection to the batter 470 oms can be connected series to the D2 (2nd diagram 24 leds).

    ReplyDelete
  7. Hi Saty,

    the above designs are meant only for mains AC operations, 12V 7ah operation will require completely different wiring.

    you'll have to make series of 3 LEDs with a resistor and make 50 such strings and then connect them in parallel for operating with a 12V batt

    ReplyDelete
  8. dear sir ,
    i have tried your circuit but there is one prblm ...i am not getting the zener diode of required value .,,,is there any substitute component which can be used in place of that zener diode

    ReplyDelete
  9. dear akshay,

    if you don't want to use a zener diode you can use a 20 ohm, 5 watt wirewound resistor in series with the input capacitor, this will take care of the surge currents.

    ReplyDelete
  10. sir one question .....what does the polyesterflim capacitor actually did

    ReplyDelete
  11. surya, the capacitor acts like a resistance for AC and drops the current to desirable limits

    ReplyDelete
  12. Hi sir,

    We are readymade dress makers. We are using power machines it has a 6V output supply from the motor. i connected 2 half hatted led in series. its is working but flickering highly. what should i do. if i want to use capacitor pls let me know which cap should i use.

    Thanks,
    Naresh

    ReplyDelete
  13. hai sir in this circuit if i keep 8mm white led any prblm and can i have the value of capasitor which is good to keep across the output of brige rectifier

    ReplyDelete
  14. Hi Naresh,

    Connect a 1000uF/25v capacitor parallel to the LEDs or the motor wires. The positive will go to the positive side of the wire and negative to negative.

    or connect a 1N4007 diode in series with the LED anode so that the supply passes through the diode then to the LEds....now connect a 100uF/25V directly across the LED series end terminals, this will solve the issue instanty

    ReplyDelete
  15. Hi Abraham, it's not very critical, you can probably use a 4.7uF/400V or a 10uF/400V capacitor at the output side of the bridge

    ReplyDelete
  16. hello sir,
    i am sorry for my bad english, sir can u help me to make led tube light which can replace fluorescent lamp with low power consumption but bright lighting

    ReplyDelete
  17. hello ayub, i'll try to publish it soon in this blog.

    ReplyDelete
  18. Change your capacity nd resistor

    ReplyDelete
  19. hai swagatam,
    can i use red leds instead of white bright leds in your home made tube light circuit?
    please reply me

    ReplyDelete
  20. hi sasi, you can use 5mm red leds, no problems.

    ReplyDelete
  21. Dear Swagatam Majumdar,
    I'm beginner and would like to ask some questions,
    this works well with 220v and 60hz?
    can use ultra bright leds?
    I use two zener diodes in series 0.5W 200v?
    I use 200v 5w zener diodes?
    if I do not find the diodor zener can use another type of diode?
    and where the value of the varistor to 220v 60hhz?
    you have a similar project?
    Thank you very much.
    best regards

    ReplyDelete
  22. Dear, the above circuit is specified for 220V AC 50Hz

    5mm ultra bright LED will do.

    use only a single 200V zener diode, two in series will not work. any other closer value will also do.

    If a zener diode is included, a varistor may not be required

    ReplyDelete
  23. what is power / volt of MOV to be used.

    ReplyDelete
  24. use MOV rated at 300v clamping voltage

    ReplyDelete
  25. Hi
    can led lamp work ac as well as dc supply
    plese explain with circuit diagram

    ReplyDelete
  26. yes it will work on both but on ac it will produce 50% less illumination....

    ReplyDelete
  27. I am not so much used with voltage and other things. I saw a circuit in net which looks like the photos added above. I want to make it for 50 led bulbs 8mm . so what changes i should bring in it. whether can i attach 50 led in in a serial way.

    ReplyDelete
  28. sir it will work fine in white LED. but the MOV is heat while connecting with pink led.....
    also connect 70 pink it MOV heat

    ReplyDelete
  29. sivanesh, yes the circuit is supposed to work with all 5mm LEDs,

    MOV has no connection with the LEDs so the EDs cannot be responsible for its heating..... and moreover MOVs will never heat up unless these are faulty, or not correctly rated.

    ReplyDelete
  30. Hi Sir, what is the difference between straw hat led and normal led and what is better?

    ReplyDelete
  31. Syed, straw hat LEDs are more sharp with their light intensity, and furthermore generate more light than the regular ones at the same current level

    ReplyDelete
  32. Sir mere area me 200v ka zener diode available nai hay or mov bhi available nahi hay laikin 100v ka zener diode available hay can i use it?

    ReplyDelete
  33. Syed, you can connect 2nos of 100V zener in series and make a 200V equivalent...

    ReplyDelete
  34. Hello Swagatam,

    Thanks for sharing such a nice circuit. I want to use 8mm LED. Can I do so and there is any change will be required. if yes, pl specify suggested changes in components and their values.
    have a nice time.

    Sudhir

    ReplyDelete
  35. Hello Sudhir,

    No changes would be required except the resistor value, which can calculated using the formula explained in the following article:

    https://homemade-circuits.com/2014/04/simplest-100-watt-led-bulb-circuit.html

    or you can also use the following software for the same:

    https://homemade-circuits.com/p/led-resistor-calculator_21.html

    ReplyDelete
  36. Hello Swagatam,

    Thanks for sharing such a nice circuit.
    I want to use 8mm leds in this circuit. Can I do so. if yes, pl guide the changes required in components and their values as well as no. of leds. can u give me an idea how much gap should keep between two 8mm leds.
    Have a nice time.
    Sudhir

    ReplyDelete
  37. Dear Swagatam,
    Thanks for your reply. do u have idea that how much gap I should keep between two 8mm LEDs.
    One more thing, I dont know forward current of my LEDs so I was trying to search a formula or method to know forward current of led but couldnt find. can you share formula or method to know the forward current of an LED. I think it is necessary to calculate the resister value.
    have a nice day.....
    Sudhir

    ReplyDelete
  38. Dear Sudhir,

    mostly it will be 3.3V for the 8mm LED, you can it connecting it to 3V supply with a series 1N4007 diode and without a diode, with diode it will not light up, and without diode it will confirming the 3.3V value.

    you can calculate the resistor value with the following formula:

    R = (U - fwd.LED)/I.

    R = resistance value required in series

    U = 330V

    fwd.LED = number of LEDs in series multiplied by 3.3V

    I = LED current specification.

    ReplyDelete
  39. Dear Swagatam,

    Thanks for reply. Actually I dont know milliamps of LEDs so I wanted the formula or method to know milliamps of LED. .

    Thanks

    ReplyDelete
  40. sudhir, there's no method or formula for identifying the current of an unknown LED, try to find the datasheet of the LED, or inquire with your local parts dealer in your area

    ReplyDelete
  41. Hi Rajesh, 150 LEDs will naturally require more current than 50 LEDs, therefore you must upgrade the input capacitor accordingly to get brighter illumination from them...try adding more capacitor in parallel to it until the illumination is satisfactory.

    ReplyDelete
  42. Dear Swagatam,

    greetings of the day....

    I have calculated 2000 ohm 3 watt resistance for series of 50 LEDs to replace 100 ohm 1 watt resistance for 8 mm LEDs in above circuit. The details are :
    Mains - 230 v
    Forward Voltage - 3.4 v
    Forward Current - 30 mA
    No. of LEDs - 50

    Using 2000 ohm 3 watt resistance is correct in series of 50 LEDs? pl advise.

    Have a nice day....

    Sudhir

    ReplyDelete
  43. Pl also advise, I read somewhere that using resistance of 10% less value (to use 90 ohm instead of 100 ohm resistance) is good to increase life of LEDs. is it right ? is it makes any difference if I use 4 watt or 2 watt resistance instead of 3 watt.

    ReplyDelete
  44. Dear Sudhir,

    actually resistor can be eliminated in a capacitive power supply if the input capacitor is calculated correctly as per the LED specs...

    for 30mA, you can use a 0.68uF/400V input capacitor and connect all the LEDs without any resistor....but make sure to use a NTC in series with the input supply, MOV can be removed

    ReplyDelete
  45. Sudhir, you mean to say it should be 10% more?? less will increase current for the LEDs and cause damage so it can be 10% more not less.

    ReplyDelete
  46. ok thanks for detailed advise..... yes I meant 10% increased resistance that will decrease current.

    ReplyDelete
  47. Hi Swagatam Majumdar
    Thank you .
    In this circuit we have not 470 ohms resistor but you say (Make 3 series of 50 LEDS each by soldering the joints. Make sure that each series comprises the given resistor of 470 Ohms.) where is this resistor in this circuit .

    ReplyDelete
  48. Hi Shayan, it's a typing mistake, it should be 100 ohms, not 470 ohms

    ReplyDelete
  49. Simple LED Tubelight Circuit You say : 150 Nos. White LEDs 5mm .
    In dont no what 150 nos. means, is it like this:
    1) Coolwhite, Viewing Angle: 15°, Liminous Intensity 17000mCd, Forward Current 20mA,Forward Voltage 3,3V
    or
    2) Coolwhite, Viewing Angle: 20°, Liminous Intensity 9000mCd, Forward Current 20mA, Forward Voltage 3,5

    ReplyDelete
  50. the LEDs must be rated at 3.3V/20mA, that's all..

    ReplyDelete
  51. I want to use more led in a single string what is the maximum number of led can I connect. Also share the circuit diagram

    ReplyDelete
  52. you can connect 93 LEDs max on each string....the series resistor will not be required in that case....

    ReplyDelete
  53. sir i wanted to run 40 led of 5 mm to 230 v in what should be the changes done to the circuit

    ReplyDelete
  54. Abdul, you can use the same circuit, just lower the input capacitor to 474/400V.

    ReplyDelete
  55. Hello sir
    Can i use the same circuit for 60 LEDS in each string and all the three strings with different colored leds i.e. one string of entirely of blue other of red and another green
    Thanks

    ReplyDelete
  56. Hello Mandeep, yes you can do it, just make sure to add a zener diode across the bridge having a voltage rating slightly higher than the total forward drop value of the LEDs

    ReplyDelete
  57. Thanks sir for your valuable response... but I am not able to find a zener diode of 200v. But 150v 1watt and 24v 1watt diodes are available. Also from the various comments I came to know about use of NTC MF75-5D9 instead of zener diode. But NTC 10D9 is the only avaliable option in my city. Is there any other method? Sir, can I use a variable resistance across the strings instead of 100 ohm resistors. Help me sir.
    Thank you

    ReplyDelete
  58. Hello sir
    I am using 200k variable resistance in the strings. Is it right?.
    Thanks

    ReplyDelete
  59. can I use two zener diodes of 120v 1watt rating joined in series across bridge as 200v is not available

    ReplyDelete
  60. Hi Mandeep, you can put the two zeners in series and achieve the required results...an NTC can be also used simultaneously but the zener should not be avoided because without zener the LeDs can become prone to fluctuations and burn in the process.

    an NTC 10D9 will also work, you can use it.

    you can use a 100 ohm pot with a series 100 ohm fixed resistor, that will ensure that the current is never exceeded over the unsafe level.

    ReplyDelete
  61. Sir,
    Can I put one150V 1watt zener and two 24V 1watt zeners in series to get the required value.
    Also 100 ohms 1 watt resistor is not available so can I use 1/2 watt resistors

    ReplyDelete
  62. 100 1/2 watt will do, please refer to my previous replies...

    ReplyDelete
  63. would also be nice to see a diagram for use with 120 VAC.

    ReplyDelete
  64. You can use to for 120V also, just reduce the number of LEDs to 25 LEDs, and the zener diode to 100V....

    ReplyDelete

Post a Comment