What is CMOS?

A compact device or system that stores data or information on the computer is used to save BIOS settings on pc motherboards. It is referred to as non-volatile bios memory. It is commonly referred to as CMOS RAM. The complete acronym of CMOS is a complementary metal oxide semiconductor.

CMOS uses a volatile, low-power complementary metal oxide semiconductor, hence the name CMOS. Because it does maintain its state, thanks to the CMOS battery, even after the system loses power, it is known as non-volatile memory or NVRAM. NVRAM typically has a 256-byte capacity. The full form of NVRAM is non-volatile RAM.

In other words, CMOS can be defined as:

Computers include an inbuilt, battery-operated semiconductor chip called CMOS that serves as a data storage device. This data includes your computer's hardware settings and the system time and date. It is also known as an RTC; the full name of this term is Real Time Clock.

How does CMOS function?

Two transistors—an N-Channel MOSFET and a P-Channel MOSFET—work together to power CMOS. The P-channel MOSFET is concurrently switched off when the N-channel MOSFET conducts, and vice versa. The cross-current stays at zero because of the low input voltage, and power is only needed during switching. Although CMOS RAMs need their power source, they only use a small amount of electricity. Much lower than bipolar or MOS circuits, the typical working voltage is 0.75 to 15 volts. Even though it is only a few millimeters, the CMOS transistor is incredibly robust. The kind and frequency of usage affect the entire lifespan.

How is CMOS used?

Microprocessors, digital watches, microcontrollers, memory elements, SRAM, i.e., static RAM, and other digital logic circuits utilize CMOS technology. Several analog circuits, including image sensors (CMOS sensors), data converters, and highly integrated transceivers for various forms of communication, also employ CMOS technology. BIOS must continue functioning even when your computer is not hooked to a power source. The battery is used in this situation.

The advantages of the technology, including its high resistance, extended lifespan, and low energy consumption, have led to CMOS being an essential component of many contemporary gadgets.

Four main features of CMOS

The CMOS menu, which employs a straightforward graphical user interface and is operated by the keyboard, provides the hardware modification choices made possible by the motherboard.

• Memory management
• Expansion port speed
• Boot device order
• Power control

These are some examples of customization options.

How long is the CMOS battery life?

Every time your laptop is plugged in, the CMOS battery is charged. The battery only loses charge when your laptop is disconnected. From the date of installation, most batteries have a lifespan of 2 to 10 years. Your battery will last longer the more you leave your laptop plugged in. However, this may change based on the environment and the use of the machine.

So how would I detect if my CMOS battery needs to be replaced?

The computer will only be able to keep the right time or date after it has been switched off if the CMOS battery dies. For instance, after turning on your computer, you could see that the date and time have been altered to January 1, 1990, and 12:00 P.M., respectively. This warning denotes a failing CMOS battery.

If one of the following warnings appears when the computer boots, it is another sign that the CMOS battery has failed.

The system battery voltage is low,

• CMOS Read Error,
• CMOS Checksum Error, and
• CMOS Battery Failure.

Benefits of CMOS

The conditions or qualities that put CMOS in a favorable or superior position are as follows:

• Offers relatively high speed.
• Low power dissipation.
• Operates over a wide range of input and output sources.
• Reduces the circuit’s complexity.
• The abundance of logic operations on a single chip.
• High noise resistance.

The most used CMOS battery is:

The real-time clock and CMOS memory are both powered by CR2032-style coin-cell batteries. The battery's expected lifespan is three years if the computer is not hooked to a wall outlet.

What can be done if the CMOS battery fails?

The computer's power cable should be disconnected. You may release static energy by pushing and holding the power button for 10 seconds to 15 seconds. Use the same type of coin cell battery to replace the old one.