How Do Computers Keep Time When Powered Off?

Discover how a CMOS battery ensures accurate timekeeping in computers, even when they're turned off.

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A computer keeps track of time while it's off using a CMOS (Complementary Metal-Oxide-Semiconductor) chip paired with a small battery on the motherboard, often called the CMOS battery. The CMOS battery powers the Real-Time Clock (RTC), which maintains the system time and date continuously, even when the computer is powered down. Replacing the CMOS battery every few years ensures consistent timekeeping.

FAQs & Answers

  1. What is a CMOS battery? A CMOS battery is a small battery on the motherboard that powers the CMOS chip, maintaining the system time and settings when the computer is off.
  2. How often should I replace my CMOS battery? It's recommended to replace your CMOS battery every 3 to 5 years to ensure accurate timekeeping.
  3. What happens if the CMOS battery fails? If the CMOS battery fails, the computer may lose track of time and date, resetting it every time it powers on.

Watch More

If you're interested in more about computer mechanisms and maintenance tips, check out our comprehensive guide on how computer hardware functions or learn about battery replacement techniques.

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