DIY Circuits:High brightness White LED Torch

White LED Torch
Heya folks! Here is an easy to build LED TORCH circuit powered using a rechargeable 3.7V mobilephone battery, actually i am using this torch light for a longtime (see my Led torch here) so i thought posting schematic of the torch might be useful for some DIY people like me as it is a very useful circuit to build.the torch light will last about 2 months with a “full single” recharge! Ain’t it cool?, the circuit uses 3 high bright white LEDs to provide sufficient light in the darkness. a recharge slot is also included in the circuit to recharge the battery using an ordinary mobilephone charger, thus this cool circuit becomes a perfect and very useful gadget!

How it works!
when you press the S1 switch, the 3.7V supply is passed to base of T1 through R2 resistor, since the T1 is used here as a switch, it turns ON and since its emitter lead is connected to the “-” (negative) or Kathode terminals of the LEDs, all LEDs get forward biased and emits light. it is that simple!. The charging section includes a Diode to protect the battery from discharging to the charger and LED1 is used as an indicator for indicating that the torch is in charging mode.

Circuit diagram

Components you need

X1 – suitable recharge slot

D1 – 1N4007 diode

R1 – 1k resistor

LED1 – Red or any color LED

S1 – on/off switch

R2 – 560 ohms resistor

T1 – 2N5551 transistor(2n3904 subst.)

LEDs2 – 3 low current white LEDs

3.7V cellphone battery

suitable case/enclosure

Click here to find out how to make a suitable enclosure for your torch!

veroboard or standard PCB.etc

the circuit can be inserted in a tiny enclosure as i did for ease to carry with you!


● Do not turn the torch ON while charging as it may destroy T1 or LEDs!

● Unplugg the charger after 1 hour of recharge, because over charging may cause heat the battery and may be explode the battery!

Designed by loneziddik


About Ztronn

hellooo i'm lsid ,i am a DIY (do it yourself) stuff loving kinda guy, i mean i love to build things and posting it on my blogs for the world to see. i love reading about technology and innovation. i love the nature,mysteries of space and of course God. no aliens. kindly let me know what you think about my simple innovations in the comments.
This entry was posted in DIY-electronics, Home made, LEDs, white LEDs (lighting). Bookmark the permalink.

3 Responses to DIY Circuits:High brightness White LED Torch

  1. T1 it’s inverted ( emitter and collector )

  2. loneZid says:

    The T1 is there to control LEDs.. i mean it works as a current limiter

  3. Simon says:

    I don’t understand what T1 and R2 are there for. It seems like they just needlessly dissipate heat and waste energy, right? Also, the LEDs have no current limiting so they are at risk of being over-driven.

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