A CMOS battery is a small, coin-shaped battery (commonly CR2032 lithium) installed on a computer’s motherboard. Its main function is to provide a tiny amount of power to the CMOS chip, which stores critical system information such as date, time, and BIOS/UEFI settings.

Even when your computer or laptop is turned off or unplugged, the CMOS battery ensures that these settings are محفوظ (saved). Without it, your system would reset to default settings every time you power it on.

🔑 Key Functions

• Maintains Date & Time – Keeps system clock running when power is off

• Stores BIOS/UEFI Settings – Saves boot order, hardware configs, etc.

• Prevents System Reset – Avoids losing settings after shutdown

• Supports RTC (Real-Time Clock) – Ensures accurate system timing

⚙️ Specifications

• Type: Lithium coin cell (commonly CR2032)

• Voltage: 3V

• Lifespan: ~2 to 10 years depending on usage

• Size: Small, round “watch battery” design