The 7805 is a popular three-terminal linear voltage regulator that provides a fixed output voltage of 5 volts. It is commonly used in electronic circuits and devices to regulate the voltage and provide a stable power supply for various electronic components. The pinout for the 7805 includes three terminals: input (Vin), ground (GND), and output (Vout). The Vin terminal is used to input the unregulated voltage, typically ranging from 7 to 35 volts, and the GND terminal is connected to the ground. The Vout terminal provides the regulated 5-volt output. The 7805 is widely used in a variety of electronic applications, such as in power supplies, voltage regulators, and microcontroller circuits. Its simple design and ease of use make it a popular choice for hobbyists and professionals alike. With its ability to provide a constant 5-volt output, the 7805 is a reliable and essential component in many electronic devices, making it a staple in the world of electronics.