The LM7805 is a classic linear voltage regulator that reduces the input voltage to a constant 5V. It is widely used in Arduino projects to convert the voltage from an external power supply to 5V. It supports input voltage between 7V and 35V and can provide a maximum current of 1.5A. It can be easily used on breadboard with TO-220 case; for high current applications, it is recommended to install a heatsink.