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.
- 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.
Sir, i want to make 5 nos (1 watt 350 ma ) led bulb what nodification i have to do above sircuit ?
What do I use for connection to use 230 volt?
Reduce C1 to 0.33uF 400 volts. Please go through the earlier comments on this. you can use IRF350 instead of ZVN2106.
A large hammer to the head normally stops them playing music.
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.
Thanks Seetharaman for the Technical Know how !!
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.
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.
If 30 leds are used in the circuit, what would the power conusumption be ?
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
Pls what is the equivalent of zvn2106, i cant get it
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
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!
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.
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.
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.
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..
ya its nice!its very bright,and it will bright ur eyes also…….
Hi Subramanian the circuit requires some improvement for 230Volt operation in indian conditions, which i will be sending to author shortly
How can i applicated this circuit for 220v power source
It will be nice that the circuit also provide changes for 220v main
what are the modifications would you suggest if the circuit is for 230v 50hz line ?can we replce fet with transistor switch ??
Reply to Traciemoo
Check this link
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.
Can someone advice how to calculate the current passing through D2 and R2||R3?