2.RTN is the abbreviation of return, and RTN stands for loop in the circuit. The power supply circuit is an important part of the motherboard, and its function is to convert the current delivered by the host power supply into a voltage acceptable to the CPU.

3. Make the CPU work normally, shape and filter the current from the host power supply, filter out all kinds of clutter and interference signals, and ensure the stable work of the computer. The main part of the power supply circuit is generally located near the CPU slot of the motherboard.