CompTIA A+ Core 1 (220-1001) Certification Practice Exam 2026 – Your All-in-One Guide to Mastery and Certification Success!

The most common voltages produced by a desktop power supply are +/- 5 volts and +/- 12 volts. This is because the power supply units in standard desktop computers are designed to provide a range of voltages that are essential for different components within the system.

The +/- 5 volts is typically used by logic circuits and common components such as the motherboard and peripherals, while the +/- 12 volts is essential for powering devices like hard drives, fans, and some other hardware components. These voltages are crucial for the functioning of various parts of the system, ensuring they receive the correct power for operation.

Other voltages may also be present, such as the +/- 3.3 volts, which is used primarily for some of the motherboard systems and integrated components; however, it is not as common as the +/- 5 volts and +/- 12 volts. The choices of +/- 9 volts and +/- 24 volts do not feature in standard desktop power supply configurations, as these voltages are not typically needed for the majority of desktop components. Thus, the correct choice underscores the critical voltages that fulfill the fundamental requirements of powering desktop computer systems.