Power supply circuits are essential components in electronic devices, providing the necessary voltage and current to operate various parts. They convert electrical energy from a source, such as a wall outlet or battery, into a usable form for devices like computers, smartphones, and appliances. These circuits often include transformers, rectifiers, and voltage regulators to ensure a stable output. Transformers adjust voltage levels, rectifiers convert alternating current (AC) to direct current (DC), and voltage regulators maintain a consistent output despite variations in input or load. Together, they ensure that electronic devices function reliably and efficiently.