How to Make a Simple 12 Volt LED Lantern Circuit


We have discussed white LEDs comprehensively through many of
my earlier articles and have learned how efficient these lights are with power consumption.
In this article we will study a very simple configuration
for making a LED lamp or a LED lantern.

New electronic enthusiasts often get confused with the
wiring intricacies while configuring many LEDs in groups.
Here we’ll see how we can connect as many as 64 LEDs for
making the proposed unit.
The circuit diagram details may be understood from the following
points:
White LEDs typically have a forward voltage drop of about 3
volts.
When operated at the above voltage level, the device is able
to produce lights at optimum levels and the spec also maintains better life expectancy.
The minimum current required at the above voltage level is
around 20 mA, which again is an optimal magnitude and is ideally suited for a
white LED.
That means for driving a single white LED in the most
straightforward way we would require 3 * 0.02 = 0.06 watts, that’s pretty
negligible compared to the relative illumination received from it.
The best thing is that as long as the above voltage and
current spec is observed, the device continues to consume 0.06 watts
irrespective of the number of LEDs connected.
In the present circuit, the maximum voltage available is 12,
dividing 12 by 3 = 4, meaning 4 numbers of LEDs can be accommodated at this
voltage and yet we are able to limit the power to 0.06 watts.
However the above calculation would make the circuit quite
vulnerable to voltage drops and if the voltage dropped even by a single volt
would make the LED too dim or might just shut them OFF, we don’t want this to
happen.
Therefore though the efficiency may drop a bit, we opt for a
configuration which would enable the circuit to work even at lower voltages. We
include only two LEDs in the series @ o.06 watts.
Now it’s all about connecting the desired number of strings
of two LEDs each in parallel until all the 64 bulbs are included in the
circuit.
However connecting in parallel would mean multiplying current. Since we have 32 parallel connections means the total consumption will
now become 32 * 0.06 = 1.92 watts, still pretty much reasonable.

The connection details can be easily traced from the given
schematic.
Your simple LED lantern is ready and may be taken anywhere outdoors
with you, probably during night time explorations.

Pats List
All resistors are = 470 Ohms, 1.4 watts,
All LEDs are = white, 5mm, hi-efficiency
Diode = 1N4007