Why are some clocks faster than others? Sometimes even with digital clocks where the timings are electronically set.

Question

Why are some clocks faster than others? Sometimes even with digital clocks where the timings are electronically set.

In: 1

Answer 1

Because there is a tolerance on the physical construction of the components that generate that timing signal. Cheap crystals used in those oscillators might have a tolerance of +-20ppm, so it might lose or gain a second or so per day.

Temperature can also change the frequency of those oscillators, or a mistake in the design, like wrong load capacitor values, can also throw the frequency off.

Answer 2

There needs to be some way to generate the signal that does the counting, and those methods are not perfect, especially the cheap ones.

Some devices connect to better time bases. Cell phones get their time from the network, and GPS units get their time from the extremely accurate clocks on GPS satellites.