White LEDs have become so common nowadays that even school kids today know how to use them for making simple LED projects. LEDs are typically used for illuminating purposes, the discussed circuit is also intended for similar applications, that is regarding a DIY LED flashlight.
White LEDs are Awesome
Before the advent of the efficient white LEDs, incandescent bulbs were the only option which could be used for making flashlights.
Though not as bright as a white LEDs, filament bulb type flashlights served the purpose quite well, until LEDs were invented, which completely transformed the scenario.
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.
The proposed circuit utilizes just a single high bright white LED, three 1.5 volt button cells and a switch.
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.