A linear power supply is a type of power supply that converts alternating current (AC) from the wall outlet into direct current (DC) for electronic devices. It uses a transformer to step down the voltage and then rectifies it, providing a stable output voltage. Linear power supplies are known for their simplicity and reliability, making them suitable for sensitive electronics. One of the main characteristics of linear power supplies is their low noise output, which is essential for applications like audio equipment and precision instruments. However, they tend to be less efficient than switching power supplies, as they dissipate excess voltage as heat, leading to larger and heavier designs.