By Bianchi Gabriele on June 30, 2021
In this project we will show you how to build your home emergency light.
The idea of the following circuit is that it must be compact and may be kept plugged into the mains socket for a permanent automatic operation. The battery can also be charged via a solar panel when the power grid is not available for a long time. We use a 6V 4.5Ah lead-acid battery; this type of battery is perhaps the most used for these purposes, it is also very cheap and can provide high currents as it has an extremely low internal resistance.
The circuit consists of two parts: the battery charging system (with an LM317 voltage regulator) and the LED driver (based on the BD140 transistor), below is the diagram.