An Automatic LED Emergency Light circuit is designed to turn ON when there is no adequate lighting or if the power supply is cut-off. Earlier fluorescent lights were used to build such circuits. But the use of LEDs has proven to provide adequate lighting for a longer period before draining the battery.

We have developed three circuits under Automatic LED Emergency Light. Two of them are designed by Mr. Seetharaman, a very valuable and important contributor to this website. We have listed the circuits here for your ease of reading. If you have any doubts; please comment on the circuit name or circuit number.

1. Simple Emergency Light Circuit

This is one of the most cost-effective (cheap) and simple emergency light circuit developed for CircuitsToday – This is an automatic emergency lamp with daylight sensing, means it senses darkness/night and turns ON automatically. Similarly, it senses daylight and turns OFF automatically.

We have designed a simple emergency lamp circuit that does not require any special equipment; even a multimeter to assemble and use. Any individual who can do a good quality soldering must be able to build this circuit successfully. This can be easily accommodated in the defunct two 6 watt tube National Emergency Lamp or any PL tube type emergency lamp. The difference will be in the working; it will work non stop for more than 8 hours. Deep discharge is taken care of by the LED characteristic and overcharge protection is taken care of by the fixed voltage regulator. This uses a simple 3-Pin fixed regulator that has a built-in current limiting circuit. The only required adjustment is preset which has to be set to ensure the LEDs just light up (it should be left at that position). The 5mm LDR is just mounted on top of the emergency light as shown in the photograph. LDR is used to avoid it lighting up during day time or when the room lights are ON. 2 LEDs are used in series; the dropping resistance is avoided and 2 LEDs light up with current that is required for a single LED,  by which energy is saved to a great extent.

Note: This circuit is developed by Mr.Seetharaman for readers of CircuitsToday. This particular circuit has been kept so simple for people who have limited access to components or in other words, this is an emergency light circuit that you can build with minimum components. In addition to the circuit diagram, He has shared photographs of the prototype he made in National emergency light and a PCB design.

Simple Emergency Light Circuit Diagram:

simple emergency light

Photographs of prototype made in National Emergency Light:

Emergency Light Circuit PCB Design:

PCB Design and Diagram of Automatic Emergency Lamp
PCB Design

2. Automatic LED Emergency Light

NOTE: Considering the doubts raised by many of our valuable readers in our Comments section, this circuit has been modified by Mr.Seetharaman, one of our valuable contributors. You can see his modified circuit here: Automatic LED Emergency Light Modified.


This is the circuit diagram of a low-cost emergency light based on a white LED. The white LED provides very bright light which turns on when the mains supply is not there. The circuit has an automatic charger that stops charging when the battery is fully charged.

The IC LM 317 produces a regulated 7 V for the charging of Battery. Transistor BD 140 drives the output. Transistor BC 548 and Zener diode controls the charging of the battery.


It is always better to connect a heat sink with BD 140. Before using the circuit output of LM317 must be set to 7V by adjusting the potentiometer.

Automatic LED Emergency Circuit Diagram:

Automatic led emergency lightNote: R3 to R14 are all 100 ohms

3. LED Emergency Light – Modified Version

The most modified and best version for this circuit is intricately explained with a neat circuit diagram and a 2 part explanation. One part is the LED lamp light circuit and the other is the battery charger circuit. All current ratings and voltage ratings are perfectly calculated with basic and clear instructions.  A further modified version is also available where under-voltage cut-off protection is provided for the LED emergency light circuit. You can find the circuit here.

We have more interesting Lighting circuits for you, please take a look:

1. LED Ramping CircuitAn interesting LED application with help of a ramping circuit.

2. Flashing LED UnitA circuit application to flash many LED’s.

3. Puff to OFF LED circuitA simple, hobby and more of a fun circuit where you can turn OFF an LED with a puff.

4. Street Light CircuitWant to build a street light application? This is the one you are looking for.

5. Light Activated SwitchA circuit application to make a switch activated when light falls upon (and vice versa).

When I was in my young days, I always had this desire to build an emergency light application. I’ve successfully built one during my high school days. I hope you enjoyed building these circuits and understood the concepts behind each. I wish you all learn more about electronics from our website. Happy learning days.


a simple emergency lamp no need for any special equipment even a multimeter to assemble and use this. Any individual who can do a good quality soldering can build this successfully. This can be easily accommodated in the defunct two 6 watt tube National Emergency Lamp or any PL tube type emergency lamp. The difference will be it will work non stop for more than 8 hours. Deep discharge is taken care by the LED characteristic and over charge protection is taken care by the fixed voltage regulator.

This uses a simple 3Pin fixed regulator which has a built in current limiting circuit. The only required adjustment is the preset which has to be set to ensure the LEDs just light up (it should be left at that position). The 5mm LDR is just mounted on top of the emergency light as shown in the photograph. LDR is used to avoid it lighting up during day time or when the room lights are on. 2 LEDs are used in series the dropping resistance is avoided and 2 LEDs light up with current by by a single LED,  by which energy is saved to a great extent.
Hope this project will be acceptable to most of our readers, who has minimum instruments.
I am attaching the photos of my prototype in an National emergency light and also the PCB design.


  1. klevis martini

    Hi, could you please add a light dependent resistor? So the leds lights up only if dark?

  2. Mauricio Zylbergeld

    Hi friends,
    Can I change the 230vAC->9vAC transformer by a 110vAC->9vDC? Do I need to change anything after the brigde?
    Thank you very much


    Dear Sir,
    Can you please tell me how the connection between voltage regulator and power MOSFET is working in SIMPLE EMERGRNCY LAMP CIRCUIT?

  4. Ricardo Zylbergeld

    Please, I’m a begginner in electronics and I have a question about the circuit #1. Simple Emergency Light Circuit:

    Are the two symbols, marked with a 10k label, one 10k potenciometer connected to a 10k resistor? And, what is this potenciometer for?

    Thank you very much!

  5. How is the base of Q2 get -volt in order to conduct
    when main failure.
    or adding a resistor to the Q2 base will solve
    the problem ?

  6. Arijit Basu

    Sir ,
    I have tried this circuit but when I connect 6V Smd led strip to the BD 140 collector terminal and ground the led was dimming very low as low as not glowing , and I was measure the voltage respect to battery negative pole on Emitter of Bd 140 is shown 6.8 V but on collector is 4.3V
    Kindly suggest

  7. Arijit Basu

    Hello sir,
    I have made this circuit but I am Using smd led strip which is actually works with 6v but when I connect led positive terminal at bd 140 collector and negative terminal to ground the led was dimming very less illumination and I have checked the voltage on bd 140 emmeter is 6.8v but on collector 4.2v so I have replaced and check bd140 with bc557 but problem not solved.

    Smd led round candle type operating voltage 6v and normally use in local made emergency light.

    Kindly suggest for solutions.

  8. Susmita Gangopadhyay

    As a final year project, we implemented the automatic LED emergency light ( 2nd one). First of all a big regards and thanks for suggesting such wonderful circuit. Now after successful implementation of the circuit, our teacher told us to o some advancement in that circuit. She told us to attach a buzzer/ alarm at that circuit. The alarm will sound whenever the power will cut off and another alarm will sound when the battery will power down. How can we implement that. Please give us some idea and if possible, please suggest the modified circuit.
    Thank you.

    With regards,
    Susmita Gangopadhyay

  9. Gaurav Maurya

    Sir! What is work of IC in this circuit?
    Please tell me.

  10. When A.C supply is on, the led bulbs dont turn off…

    Any reason??

  11. Susmita Gangopadhyay

    I have chosen automatic LED emergency light (using LM 317) as my final year project. I have to make a powerpoint presentation on this. But I cannot find sufficient information. Please help me with further details.

  12. Colin Mitchell

    The Simple Emergency Light Circuit does not work. The transistor keeps the circuit turned OFF all the time !!!!!!

    • Paul kelley

      what about an emergency light with addition of a light sensor to keep the lights OFF when the AC power is off but the lights are not needed. So the batteries will be still fully charged when it gets dark

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  14. Thank you for sharing such a good post, hope to see more post weiahflrygds.

  15. ocharive john

    I like this circuit but I have a 12v ups battery how can I use the battery with this circuit without any problem.
    thank you.

  16. Hi sir. Do i know how this automatic led emergency light can detect the main power cut-off?


      i am basically electrnics side week,sir,please help me

  17. praveenkumar

    hi. I have a some problem 16 ohms 5 w do not get it at the local electronics store. I wanted to know if there is any equivalent and i want to use 30 leds what is the changes please reply

  18. praveenkumar

    Sir I have a another problem 16 ohms 5 w do not get it at the local electronics store. I wanted to know if there is any equivalent and also how to give power supply indicate light please reply soon.

  19. praveenkumar

    sir i want to use 20 leds in your ckt plz what are the changes required plz its very argent sir.

  20. hi. I have a small problem with endurance of 16 ohmis 5 w do not get it at the local electronics store. I wanted to know if there is any equivalent. thank you very much. Jose

  21. John Barua

    Sir I need your advice at present I have an UPS which is no more in used for the Pc cos ever one in the house have got laptops, the UPS I want to used as an emergency light pls advice me as how many LED are require dim i for the 12v UPS and where can I get them or could you give me a circuit diagram where I can build it. It should be bright as the tube light and last for 4 to 6 hrs with the UPS my contact no 9764848146 Goa
    Regard John

  22. vishnu vm

    Sir. can I use five 1watts led in this circuit

  23. Hoa sen vàng

    Hi, the Automatic LED Emergency Circuit Diagram is auto charge (transistor LM317) circuit battery 6volt. i don’t how long it’s full (6,7 volt). that’s mean – when low power under 6volt, and (I) charge begin supply to battery.thanks

  24. Dear Sir,
    I m working on the circuit 1 and I dont have much knowledge about it so can you please explain me the procedure, gladly i want to say your contribution towards this field and helping to beginners who are not very well known about circuits . Thank you …..
    Awaiting for your reply

    • Seetharaman

      The Emergency light is a simple one with day light sensor also. The charger circuit consists of a 7808 fixed voltage regulator. The auto function is taken care by MOSFET (the day light or with other light sources you do not require this light) hence an LDR(light dependent resistance) is used to sense the ambient light and to switch of the light. Hope this explanation will do.

  25. brunasse bitch

    Oո voit direct que vous cοnnaissez superbement bien ce sujet

  26. Sir,
    Is the readymade PCB of the Auotmatic LED emergency light available for purchase in circuitstoday. If available, kindly help as to how to purchase the PCB?

    • Seetharaman

      Remove two 1K resistaces, BC548B and LDR. no other component need be removed. The auto off of emergency light, during external light availability will be lost.

      • sir can you please provide abstract and documentation pdf for automatic emergency light using LM317 ic

  27. Kiran Pardeshi

    Dear Seetaraman Sir,

    Please provide me 12v LED emergency light. Also same LED light should be used on 230VAC.

  28. seetharaman sir can u pls provide us with the circuit diagram of solar led street light with automatic intensity control.

  29. can tell me the name of software by which I can develop any electrobic circuit and abive circuit,before making it in hardware,pls it is urgent,& if possible then give me the download link,

  30. Dear Sir,
    I am working as an electronics engineer.
    I am interested in charging light concept.
    Do you have pcbs and components ready for assemble?
    at what cost?
    I am staying at hyd.

  31. Mr. B. S. Makwana

    LED Emergency Light simple Emergency Light Circuit Diagram shown in photo

    PCB & All component is available from you please sent cost if possible send sample to me for trial.

    Makwana B. S.

    CSMCRI, Bhavnagara, Gujarat

  32. dear sir
    i am final year our final year we project simple emergency lighting system with using(a transformer 230 to 6v,1 thyristor,3 resistance,1 capacitor,3 diode,1 lamp,1 battery ).we could not find any information about this,so sir give me some information about this.please,please sir.please mail me some information about this.

  33. deekshitha

    good evening… can i do this circuit on ‘Bread Board’ (small presentation purpose)

  34. ahmed mokhtar ahmed el sonbaty

    I am retired electronic engineer,,,and have my special activities in electronic lightings,,,,I need the available circuits in lighting from battery,,,,12 volts,,,please feed me by any avaialable circuits,,,,for the two lamps,,,(20 watts&40 watts),,,,GOD bless you my brother

  35. zeyede seifu

    I’m Intrested to do project on automatic emergency LED light I need ahelp

  36. hi Seetharaman, can i use a 2k on VR1? 2.2k is not available in my area. Please reply

    • Seetharaman

      you can use anything up to 5k. 2k may not be sufficient.

      • hello sir,i want 2.1 audio system(power full) circuits and components details

  37. hi Seetharaman, can i use a 2k on VR1? 2.2k is not available in my area. Please reply.

  38. Krishna chaurasia

    Sir ..
    My name is krishna and i want to do project about SMOKE DETECTOR SO Plz you send component list and also curcuit diagram along with simplied.

  39. HI,
    instead of 6 vdc circuit, do you have 12v circuit?. It is for 12 vdc LED strip get on when power is fail. I have already 12 vdc 9 amps battery and led strips with me.

    with regards
    shaji dominic

    • seetharaman

      Hi Shaji you can use the thyrister battery charger appeared earlier in our column. which will be best suited for you. any 14 volt regulated limited to 2 Amp current can be used.

  40. can I get the circuit board of automatic led emergency light that is published i n circuit Can i get a circuit to drive 4 led light of 4 watts with 12 vdc to light a home.(16 watts circuit)

    with regard
    shaji dominic

    • Hello Shaji,

      At present we don’t provide circuit board of any of our circuits. We dont have the dedicated resources to implement this as a service. We will definitely consider this in future.


  41. Dear seetharaman,
    I need your help.Pls clarify my doubt i have one V guard stabilizer faulty,output is not come.Inside the stabilizer fixed one Transformer and PCB only.How to find the problem.inside the PCB using TIP122 & LM358 IC. pls reply.