Real-time clock (RTC) is an electronic device that can output actual time like a clock. It is usually an integrated circuit, so it is also called a clock chip. This term is often used to refer to a device that has this function in a personal computer, server, or embedded system, but many systems that require precision will have this feature.

Frequency Characteristics

Dimensions

The real-time clock uses a quartz crystal resonator as its source, but some use the frequency of the AC power source. If a quartz crystal resonator is used, the frequency of the majority of the resonator will be the same as the resonator frequency in the quartz clock, which is 32.768 kHz. This frequency is exactly 215 times per second, which is convenient for use with a simple binary counter.

A system without a real-time clock can also calculate the actual time, but using a real-time clock has the following advantages:
1.Low power consumption (especially important when using auxiliary power)
2.Let the main system handle more time-sensitive work
3.Sometimes it is more accurate than the output of other methods.