LEDify It!, mobile 3-watt LED Lamp

A traditional hand-held torch could hardly be described as a cutting-edge piece of technology; in fact it's probably the exact opposite, circuits don’t come much simpler! Text books have for years used a battery, light bulb and switch to describe just what a circuit is. We are also aware of the shortcomings of the filament lamp; the light dims as the battery discharges and occasionally you need to replace a burned-out bulb. Why not treat an old torch to a 21st century make-over? Replace the bulb with more efficient LEDs, the 5 mm 70 mW types will not be very illuminating but 1-watt white LEDs are now reasonably priced.
It’s not quite as simple as removing the bulb and replacing it with an LED.