Question

Which of the oscillators doesn't come under the category of low frequency oscillators?

• A. RC phase shift oscillator
• B. Wien bridge oscillator
• C. Twin T oscillators
• D. Crystal oscillator

Hint:

Oscillator Types & Frequency. Low Frequency (< 1 MHz, Audio): Typically RC networks (Wien Bridge, Phase Shift, Twin-T). High Frequency (> 1 MHz, RF): Typically LC circuits (Colpitts, Hartley) or Crystals. Crystal oscillators offer high frequency stability.

Answer 1

The Correct Option is D

Oscillators are often categorized by their operating frequency range and the type of frequency-determining element used
- Low-frequency oscillators (typically audio frequencies, roughly<1 MHz) commonly use Resistor-Capacitor (RC) networks to determine the frequency
Examples include RC phase shift oscillators, Wien bridge oscillators, and Twin-T oscillators
- High-frequency oscillators (Radio Frequencies, RF range, MHz to GHz) typically use Inductor-Capacitor (LC) resonant circuits (like Colpitts, Hartley oscillators) or resonant crystals (Crystal oscillators)
Crystal oscillators utilize the piezoelectric effect of a quartz crystal, which provides a very stable, high-Q resonance at a specific frequency
While crystals can be cut for lower frequencies, they are primarily known for their stability and use in higher frequency applications (kHz to hundreds of MHz) compared to standard RC oscillators
Therefore, crystal oscillators are generally not categorized as low-frequency oscillators in the context of RC types