White LEDs are so efficient that they produce 4 times more light than a conventional incandescent type flashlight yet consume 60% less power.
No surprise why white LEDs are being considered as the future option for all lighting applications.
The LED flashlight circuit explained here is very simple, and it simply requires to follow the instructions as given for making it successfully.
White LED Forward Drop Voltage
As we all know, a white LED typically needs a 3.5 volt supply for illuminating directly, without the need of any current limiting resistors.
Therefore here we connect the three 1.5 volt button cell connections directly across the LED terminal for switching it ON and for getting the intended illumination from it.
Being low in current the 4.5 V output from the cells does not produce any damaging effect, rather automatically adjusts to illuminate the LED very brightly.
Now add a switch anywhere in between the above cell and LED connection, it becomes switchable manually, your simple LED flashlight circuit is ready.
The discussed flashlight arrangement will require a proper casing for holding all the parts in place securely so that it can be comfortably operated by hand.
A sample design is shown below, which may be copied for making the enclosure for the above circuit.