CMOS Battery

A CMOS battery, also known as a motherboard battery or RTC (Real-Time Clock) battery, is a small, round-shaped battery found on the computer’s motherboard. CMOS stands for Complementary Metal-Oxide-Semiconductor, which refers to the technology used in the battery’s construction.

The primary function of a CMOS battery is to power the CMOS chip on the motherboard, which stores the system’s BIOS (Basic Input/Output System) settings. These settings include information such as the system time, date, hardware configuration, and other essential parameters necessary for the computer to boot up properly.

When the computer is powered off or unplugged, the CMOS battery ensures that the BIOS settings are retained by providing a constant power supply to the CMOS chip. This enables the system to remember its configuration even when the main power source is disconnected.

CMOS batteries typically have a lifespan of several years, but over time they may gradually lose their charge or become depleted. When the CMOS battery is exhausted, the BIOS settings may be lost whenever the computer is powered off or restarted, resulting in issues such as incorrect system time, booting problems, or the need to reconfigure the BIOS settings every time the computer starts.

Replacing the CMOS battery is a straightforward process and involves opening the computer case, locating the battery on the motherboard, and carefully removing it. The most common type of CMOS battery is a small lithium coin cell, often referred to as a CR2032 battery. Once the old battery is removed, it can be replaced with a new one of the same type.

In summary, the CMOS battery is an essential component that provides power to the CMOS chip, ensuring the retention of BIOS settings when the computer is powered off. It plays a crucial role in maintaining system stability and proper functioning.