white led flood lamp circuit schematic

White LED Flood Lamp Circuit

This white LED flood lights illuminates your porch with cool white light. The circuit is too simple and energy saving design. Its current consumption is practically nil but can provide light like a 20 watt CFL lamp. It is directly connected to AC lines to eliminate a bulk transformer.

Ultra white LEDs are now replacing the fluorescent lamps due to its energy saving property and simplicity of design. White LED emits 1000 to 6000 MCD light and easily works on 3 volts at 20 mA. White LEDs are available as spot light and diffuse type versions. Different sizes like 3mm, 5mm and 10 mm varieties are now common. High watt single white LED is also available. White LEDs was introduced in 1990 which uses Indium Gallium Nitride (InGaN) as the semiconductor. White LED contains a blue chip with white inorganic Phosphor.

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When blue light strikes the phosphor, it emits white light. The circuit uses capacitive reactance to drop high volt AC to low volt AC. This reduces power loss due to heat dissipation. The value of the AC capacitor can be calculated using the formula X c= 1/ (2 π f C) where, Xc is the reactance in ohms, C the capacitance in farads and f the mains frequency. Xc = Vrms / I where Vrms is the input voltage and I is the current flowing through LEDs. The low volt AC (around 100 volts) dropped by C1 is then rectified by a full wave rectifier formed of D1-D4.

Schematic of the LED Flood Lights Circuit

white led flood lamp circuit schematic

Capacitor C2 act as a ripple remover and buffer. Zener diode ZD regulates DC to 69 volts and prevents excess reverse voltage across the LEDs during the negative half cycles. R1 is a must in the circuit to bleed the stored current from C1 when the circuit in unplugged. C1 can store more than 400 volts for many days if R1 is not connected. This can give a lethal shock.

R2 reduces the inrush current. 20 LEDs are connected as a string to obtain luminance equal to 20W CFL. Enclose the circuit in a shock proof case. If a reflector is provided behind the LEDs, it will give a flood light appearance.

Important! Do not touch any points or trouble shoot when the circuit is connected to mains.

Caution This is an AC powered circuit and can give fatal shock if handled carelessly. Do not construct the circuit unless you are competent to handle high volt circuits.


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  • Listin Augustine

    Hi sir, can i use this same circuit to power 10 numbers of 2 watt smd led or is there any changes to be made. Pls help me by giving me a reply at my mail id . Your help will be greatly appreciated. Thank you.

  • Sk sharif

    Can i Use 4 or 5 Zener in series,and can i use 1000 uf 160V Capacitor.

  • Sk Sharif

    Can I Use 3 Or 4 Zener In series?Plz Help me as soon as possible.

  • h.i.singh

    Dear Sir,
    I didn’t understand one thing. As fer I know C1
    474K can supply 12v 25 mA
    105K can supply 24V 40 mA
    225k can supply 24v 100mA
    I got that from how could it possible lightning 20 led in series that have 20×3.2=64v needed??
    On the other hand I got another same circuit in this site ( is 12v 100mA.
    Please sir explain it to me.

  • Ranjan

    Sir, can i use 6 and 10 no. 0.25w led in this curcuit? And what should be change in curcuit for this?

  • kishan

    Can i replace c1 with other capacitor?
    When replace it than which voltage and value capacitor use..

  • sebin

    Sir would you please help me to make a rectifier circuit containing 5 led’s

  • nitesh majumdar

    sir can u tell me… if i wll use a 20w cfl circuit than howmany 3v leds can use… or if i want to assamble 1w led… than what can be change on circuit….

  • C.Mitra

    Dear All members,
    The circuit give here is a very practical LED lamp circuit. It is the most commonly used circuit today for powering all kinds of low current devices, especially LED’s. I have one word of caution regarding the use of this circuit for LED lighting purposes. This circuit is quite sensitive to the incoming mains voltage. White LED’s are also sensitive to voltage and current, a slight increase in the current can be catastrophic and quickly lead to the destruction of the LED. Please do not use this circuit with cheap power inverters at home, since these inveters have very bad voltage regulation, and sometimes the output voltage can go upto 260V AC with low loads. Chinese LED bulbs widely use these circuits, and I have lost a number of these bulbs while using on inverter power.
    The zener diode in this circuit may provide some amount of protection, but it is not recommended to use zener diode in this manner since it may get quite hot and waste a lot of power.
    Any views contrary to mine is welcome…

  • Pardeep

    Dear Sir,

    From which calculation can I calculate the value of resistance R1 R2 & C1.