Multiple choice Which of the following is the most stable oscillator? Wien bridge oscillator Colpitts oscillator Hartley oscillator Crystal-controlled oscillator Reveal answer Fill a bubble to check yourself D Correct answer Explanation Crystal oscillators use the piezoelectric effect of a quartz crystal to provide a highly stable resonant frequency. This stability far exceeds that of LC oscillators like Hartley or Colpitts, or RC oscillators like the Wien bridge.