Readymade emergency light kit setup diagram



This is how a 12 volt 40 watt ready made emergency CFL/TL circuit looks like. This circuit consists of one power transformer, one 2N3055 transistor wit heat sink, two high watt resistors(brown) in series to apply saturation voltage to the transistor base, 0.1uF ceramic capacitor(green) for soft start and frequency maintaining, one small(yellow) 0.01uF capacitor with a IN4007 diode to protect the transistor from reverse feedback voltage from transformer, two 1000uF capacitors(blue), one for charge current filtering, another for holding emergency system off during charging, the three IN4007 diodes below are for charging rectifier section, and the 4?th one is for giving negative voltage(buffered by a 1000uF capacitor) to the base of transistor for switching it off during charging.




The two open connections from the transformer(down of the picture) goes to the terminals of CFL, or direct tube light(without any choke) or to CFL lamp<40W. The 12V & 12V connectors (in the right-up and right-down) goes to 12Volt battery -ve & +ve respectively. The inner three connectors in the right goes to charging transformer’s secondary(output) of 12-0-12 volts section. Though at 40Watt, the circuit uses about 3.5Amps of current, a very low ampere rated switch can be installed here. The switch will be between the base and emitter terminals of the transistor(the two points in the left except the screw points). Thus, the setup complete.


The kit costs only Rs. 50~55/-  as per current(Oct-2010) market price.

Comments on this article before 07-12-2011,

  • Anish KS on October 25, 2010 – 9:51 pm

    Why Using this now, try with BIG White LED’s. Me using 20 White LED’s, Cost each 5 with a 12V Ups battery. its back up in hours, enough light. try it.

    Arup Reply:
    October 25th, 2010 at 10:14 pm

    LED are very energy efficient, but we cannot use it in home lighting, as replacement in loadshading etc. Replacing a 40Watt T/L with that Jumbo LEDs will take around 200-250 LEDs, which will cost a lot w.r.t the cost of this circuit.

  • Anish KS on October 26, 2010 – 10:03 am

    This Old Method Man, Using this Circuit the Tube will dark its end within few days.

    LED Cost little bit high, for me the 20 LED cost 100. me them as 2 in Series with a Resistor 220Ohm, so total 10 Units and these connected to 12 V battery. Back up is terrific.

  • naveen on December 27, 2010 – 1:41 pm

    hi bro,
    i want this circuit diagram, please post circuit diagram

    Arup Reply:
    December 29th, 2010 at 9:11 am

    Reffer to this article for schema

  • naveen on December 30, 2010 – 8:59 pm

    i don’t understand this circuit,

    is this kit available in electronic shops?

    Arup Reply:
    December 31st, 2010 at 7:49 am

    This is available, just take a printout of the circuit (1st pic) and show it to retailer, or otherwise, ask them for 12Volt 40Watt Emergency kit which is by 2N3055 transistor.

  • patrick on October 1, 2011 – 3:05 am

    Hello Arup,
    This is a lovely circuit, I have some 26watt CFL with 2 pins and they need drivers, hence can u suggest where i can buy the same, if u have a circuit diragram also, pls email with the PCB layout, thanks for the help

    Arup Reply:
    October 1st, 2011 at 4:07 pm

    I couldn’t understand. Can you explain in details?

  • patrick on October 2, 2011 – 2:31 am

    Hello Arup,
    I have some 26 watt CFL lights, Can u pls suggest a driver circuit diagram for the same.

  • patrick on October 2, 2011 – 1:48 pm

    Hello Arup,
    Can u details of the transformer, such as thickness of wire and how many turns in primary and seconday. what is the rating of the brown resistor etc.,
    thanks for ur help

    Arup Reply:
    October 4th, 2011 at 3:34 pm

    The brown resistor is 100E 5Watt.
    You want to light 26Watt CFL through 12Volt battery. Isn’t it? Then use this one.
    Please feel free to browse my blog thoroughly and you’ll get most answers to your doubts.

  • Arpan Panja on October 6, 2011 – 8:23 am

    I bought a same type of kit. but cannot find out +12v & -12v terminals for battery connections.I saw pages also.
    that circuirt is different. send me your circuit diagram posted by you(picture).

  • Arup on October 7, 2011 – 8:53 am

    There is a big capacitor in the board, find it. Apply 12volts to it’s +ve and -ve terminals.

  • pavan on October 8, 2011 – 12:29 pm

    Times are gone for using t/l for Emergency-ckts.leds offer great efficiency as well as better back up. one can go with led strips.

  • ANU JIYA on October 13, 2011 – 6:57 pm

    What’s the value of T1?

    Arup Reply:
    October 14th, 2011 at 2:37 pm


  • Prasun on November 15, 2011 – 5:35 pm

    what is the value of transformer in the kit?

    Arup Reply:
    November 16th, 2011 at 3:02 am

    Ask shopkeeper for a 12/40 emergency transformer.

  • daniel on November 25, 2011 – 12:53 am

    good day can u give me the schematic of this thank you very much…

    Arup Reply:
    November 25th, 2011 at 10:35 am

    You’ll find a link in the above comments

You may also like...

14 Responses

  1. patrick says:

    Hi arup,
    I want to send you a picture of the 26watt cfl, how should I sent it to you.

Leave a Reply

Your email address will not be published. Required fields are marked *

Useful one ? Share it !