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.
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
veroboard or standard PCB.etc
● 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