PC Power Supply Output Type The regulated output rails delivered by a computer power supply to the motherboard and peripherals are provided as which type of current?

Introduction / Context:
Switch-mode power supplies (SMPS) in PCs convert AC mains into stable DC voltages for logic and storage devices. Knowing that the outputs are DC is essential for correct measurement, troubleshooting, and safety practices.

Given Data / Assumptions:

• Typical ATX/ITX PC power supplies provide +12 V, +5 V, +3.3 V DC rails.
• Mains input is AC, but the output to the system is DC.
• Terminology like “trickle” refers to standby DC power (+5 VSB).

Concept / Approach:

The SMPS rectifies and filters incoming AC, then uses high-frequency switching and regulation to produce stable DC outputs. Digital electronics require DC for proper biasing and operation. Measurements of rails should be made on DC voltage scale with a multimeter.

Step-by-Step Solution:

Verification / Alternative check:

PSU specification labels, ATX standards, and motherboard manuals explicitly list DC outputs. Oscilloscope and DMM measurements confirm DC with small ripple components within spec.

Why Other Options Are Wrong:

AC: Present at the input, not supplied to the logic rails. Amperage / resistive / trickle: Not types of current; “trickle” is a standby DC rail concept, not the main output type.

Common Pitfalls:

Measuring rails on AC scale; confusing ripple with AC output; overlooking the standby rail behavior when the system is “off.”

Final Answer:

DC