eli5: How do you tell a computer what time it is? You can tell a mechanical clock to tick every second using physics but how do you do the same to a non-moving electronic device?

Question

eli5: How do you tell a computer what time it is? You can tell a mechanical clock to tick every second using physics but how do you do the same to a non-moving electronic device?

In: Technology

Answer 1

A real time clock in a computer is usually a battery powered counting device. What it counts are vibrators of a quartz crystal, which occur at a set speed.

The computer software then is told, either by a server or human input, what time it is, and it counts up the time from there.

Since the clock is counting, even when the system is powered off, it can adjust the system clocks to the correct time when it powers back on.