Analog and electronic circuits

Why are crystal oscillators widely used as clock sources for watches and microcontrollers?

  1. ABecause their output power is very high
  2. BBecause the quartz resonator has a very high Q, giving an accurate and stable frequency
  3. CBecause their frequency can be freely changed over a wide range
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Answer: B. Because the quartz resonator has a very high Q, giving an accurate and stable frequency

A quartz resonator is a mechanical resonator using the piezoelectric effect, with a very high Q of tens to hundreds of thousands and little frequency drift with temperature. This makes accurate, stable oscillators possible. It is not suited to large frequency changes.

  • A. Crystal oscillators have low output power; that is not their advantage.
  • B. Correct. The high Q gives an accurate and stable frequency.
  • C. A crystal's oscillation frequency is nearly fixed and cannot be changed over a wide range.
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