How Do Computer Clocks Work Without Power? Understanding RTC & CMOS Batteries

Discover how computer clocks keep time without power using CMOS batteries and Real-Time Clocks (RTC).

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Computer clocks often rely on a small battery, like a CMOS battery, to maintain time even when the main system is off. This battery powers the Real-Time Clock (RTC), ensuring your computer's date and time settings are retained. Regularly check and replace this battery to avoid timekeeping issues.

FAQs & Answers

  1. Why does my computer clock reset when it's turned off? Your computer clock resets due to the depletion of the CMOS battery, which keeps the Real-Time Clock functional when the system is powered down.
  2. How often should I replace my computer's CMOS battery? It's recommended to replace the CMOS battery every 3 to 5 years, or when you notice your clock losing time.
  3. What happens if the CMOS battery fails? If the CMOS battery fails, your computer may lose time settings, reset BIOS configurations, and you may encounter boot errors.
  4. Can I use my computer without a CMOS battery? You can operate your computer without a CMOS battery, but you will lose date and time settings each time the computer is turned off.