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Simple LED Tubelight Circuit

Explained in a very lucid style and through a schematic the complete construction of a simple LED light tube circuit using 20 mA, 5 mm high bright white LEDs. The circuit 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.

150 LED transformerless tubelight circuit

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!

adding a 200V zener diode for surge protection to LED tubelight

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.

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:

50 LED tubelight prototype

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

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

courtesy: Bibin Edmond

simple capacitive power supply for LED tubelight

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

LED tubelight using transformer rectified power supply circuit

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:

Circuit Operation

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 transformreless 220V LED tube light circuit

LED Specifications and Datasheet

Continuous Forward CurrentIF30mA
Peak Forward Current(Duty /10 @ 1KHZ)IFP100mA
Reverse VoltageVR5V
Operating TemperatureTopr-40 ~ +85
Storage TemperatureTstg-40 ~ +100
Soldering Temperature (T=5 sec)Tsol260 ± 5
Power DissipationPd100mW
Zener Reverse CurrentIz100mA
Electrostatic DischargeESD4KV

LED Absolute Maximum Ratings (Ta=25℃)

ParameterSymbolRatingUnit
Continuous Forward CurrentIF30mA
Peak Forward Current(Duty /10 @ 1KHZ)IFP100mA
Reverse VoltageVR5V
Operating TemperatureTopr-40 ~ +85
Storage TemperatureTstg-40 ~ +100
Soldering Temperature (T=5 sec)Tsol260 ± 5
Power DissipationPd100mW
Zener Reverse CurrentIz100mA
Electrostatic DischargeESD4KV
SHARING IS CARING!


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!



68 thoughts on “Simple LED Tubelight Circuit”


  1. Howdy, Friend! Interested to Learn Circuit Designing? Let's Start Discussing below!
  2. 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

    • 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

    • 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

      • 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.

      • 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

  3. 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

  4. 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

  5. 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 .

  6. 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.

    • 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.

  7. 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

    • 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

  8. 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.

  9. 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

    • 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

  10. 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

    • 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.

  11. 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

  12. 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

  13. 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?

    • 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.

  14. 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.

  15. 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

    • 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

  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

  17. 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

    • 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

  18. 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

    • 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

  19. 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

    • 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.

  20. 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

  21. 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).

  22. 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?

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