Super bright LED night light

john October 15, 2010 27 Comments

Description.
Here is the circuit diagram of a super bright LED night lamp that can be operated from the mains supply. Bridge D1 is used to rectify the AC mains voltage. The capacitor C1 and resistor R1 forms the current limiting circuit. 10 ultra bright white LEDs are wired in series to produce the required light. The n-channel FET Q1(ZVN 2106) is used to automatically switch the lamp OFF at full light. The photo cell resistance is set to be 100K at full brightness. Anything less than this 100K will instantly switch the LEDs OFF. Zener diode D2 is used to limit the peak voltage across C1 during the switching of LEDs.

Circuit diagram with Parts list.

Notes.

  • Assemble the circuit on a general purpose PCB.
  • The capacitor C1 is a 0.68uF/250V Polyester capacitor.
  • Capacitors C2 and C3 must be rated at least 50V.
  • If 1A Bridge is not available make one using four 1N4007 diodes.
Comments
  • Suresh
    July 23, 2014

    Sir, i want to make 5 nos (1 watt 350 ma ) led bulb what nodification i have to do above sircuit ?

  • June 19, 2014

    What do I use for connection to use 230 volt?

    • Seetharaman
      June 20, 2014

      Reduce C1 to 0.33uF 400 volts. Please go through the earlier comments on this. you can use IRF350 instead of ZVN2106.

  • suleman
    October 31, 2011

    Good One

  • Simon B
    August 1, 2011

    A large hammer to the head normally stops them playing music.

  • ravi
    July 30, 2011

    Hi good morning sir.daily am travelling in train approx 150km.in this train the people will play music player in china mobiles with lot of sound.this is too much irritating to co passengers.if you have any ckt to jam this player please send to my email.thanks.

  • rohit kumar
    May 16, 2011

    Thanks Seetharaman for the Technical Know how !!

  • Seetharaman
    May 15, 2011

    You can use 30 LEDs replace D2 with 3 X 36 volt 1/2 watt zener diodes in series to achieve 108 volts. 35mA will be DC current through the LEDs. The DC voltage across the bridge rectifier will be 1.3 volts. the drop across R2 will be 0.2volt. Normal thumb rule for filter capacitor for 100Hz(full wave rectifier) ripple is 1000uF per amp load for acceptable level ripple. you can calculate for 35mA. The drop across R3 will be voltage across D2 – 2.5 volts. Drop across C1 will have both AC and DC components. Measurement will be difficult without proper expensive multimeter.

  • rohit kumar
    May 13, 2011

    Hello Seetharaman,

    I have some questions regarding the circuit?
    If 30 leds are used in this circuit.

    -what is the voltage drop across C1.
    -What is the voltage across the bridge rectifier.
    -what is the Current in the circuit (mA)
    -What is the voltage drop across the resistor R2 & R3
    -How do we calculate C2 for ripple free.

  • rohit kumar
    May 13, 2011

    Hello Seetharaman,

    If 30 leds are used in the circuit, what would the power conusumption be ?

  • Seetharaman
    April 23, 2011

    Hi Abiola You can try IRF540.
    Hi Janong you have to replace D2 from 39 volts to 120 volt zener. C2 should be rated for 250 volts.
    Hi Prashanth this will hardy consume any current during day time.
    Also go through my comments on oct 16th
    For 230 Volt operation reduce C1 0.33uF 400 volt no other change is required

  • Raji abiola
    April 21, 2011

    Pls what is the equivalent of zvn2106, i cant get it

  • February 7, 2011

    1. how can i improve the no. of led that will be connected in series with the circuit ,
    2 does making 30 led’s as a load vary their brightness?? is there a revision in the circuit that was presented here so that it can handle the 30 led’s

  • Prashanth
    January 13, 2011

    Hello Mr. Seetharaman, Will this circuit be consuming any power when it is day time?

    I want to make a larger version of this as a porch light and leave it on permanently!

  • Seetharaman
    October 16, 2010

    Hi Friends the circuit is correct but one line is missing. connect negative of the bridge to MOSFET source line, then only the circuit will get completed. For 120 volt 60Hz 250Volt capacitor is OK for 220 volts 50Hz the capacitor to be reduced and its voltage rating to be increased to 400volt.

  • Che
    October 15, 2010

    Right! what the last comment (before me) states is correct… the bridge rectifier is connected wrongly. for 220V, the polyester capacitor C1 should be rated 400V not 250V.

  • Srinivas D
    June 26, 2010

    I really doubt the connection made to bridge rectifier, it is reverse, where P and N of the diode meets we connect input (120v) and from N joint and P joint of the diodes we take output. Please correct if I am wrong.

  • deepak
    June 26, 2010

    why are all the LED’s connected in series..the voltage across each of them will not be the same…isn’t it better to connect all the LED’s in parallel with an appropriate resistor so that all LED’s have the same voltage across them..

  • raul
    April 4, 2010

    ya its nice!its very bright,and it will bright ur eyes also…….

  • Seetharaman
    March 10, 2010

    Hi Subramanian the circuit requires some improvement for 230Volt operation in indian conditions, which i will be sending to author shortly

  • W.SIDIK
    February 24, 2010

    How can i applicated this circuit for 220v power source

  • N.Subramanian
    February 16, 2010

    It will be nice that the circuit also provide changes for 220v main

  • Sree
    February 1, 2010

    what are the modifications would you suggest if the circuit is for 230v 50hz line ?can we replce fet with transistor switch ??

  • pavan
    December 22, 2009

    thanks for good circuit. But i really do have some doubts….i.e.,
    1.any changes to be made if input is 230V,50hz across mains.
    2.how much does a photocell mentioned here costs.

  • KT
    November 30, 2009

    Can someone advice how to calculate the current passing through D2 and R2||R3?

    Thanks.

  • September 29, 2009

    good ckt

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