15.01.2024 Views

CompTIA A+ Certification All-in-One Exam Guide

  • No tags were found...

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

into DC current, is like a person sucking on a straw on the end of this pipe. It

takes gulps only when the current is fully pushing or pulling at the top and

bottom of each cycle and creating an electrical phenomena—sort of a back

pressure—that’s called harmonics in the power industry. These harmonics

create the humming sound you hear from electrical components. Over time,

harmonics damage electrical equipment, causing serious problems with the

power supply and other electrical devices on the circuit. Once you put a few

thousand PCs with power supplies in the same local area, harmonics can even

damage the electrical power supplier’s equipment!

Good PC power supplies come with active power factor correction (active

PFC), extra circuitry that smooths out power coming from the wall before

passing it to the main power supply circuits. This smoothing process

eliminates any harmonics (see Figure 7-26). Never buy a power supply that

does not have active PFC—all power supplies with active PFC will announce

it on the box.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!