Which term describes the electronic circuit that uses a piezoelectric crystal to stabilize the oscillator's frequency?

Which term describes the electronic circuit that uses a piezoelectric crystal to stabilize the oscillator's frequency?

• A. Use of Crystals
• B. LC Tank Oscillator
• C. Crystal-controlled Oscillator
• D. Hartley Oscillator

Answer: (C)

The frequency-determining element is a piezoelectric crystal, which has a very sharp resonance and high Q. When the crystal is placed in the feedback network of an amplifier, it acts as a precise reference, so the circuit will oscillate primarily at the crystal’s resonant frequency. This makes the oscillator’s frequency stable over changes in temperature, supply, and aging, more so than with many other frequency-determining networks. This setup is described as a crystal-controlled oscillator—the crystal controls the frequency. The other options describe different concepts: an LC tank oscillator relies on an inductance-capacitance network to set frequency, and a Hartley oscillator refers to a particular amplifier feedback topology. A vague “use of crystals” doesn’t name the circuit type.

The frequency-determining element is a piezoelectric crystal, which has a very sharp resonance and high Q. When the crystal is placed in the feedback network of an amplifier, it acts as a precise reference, so the circuit will oscillate primarily at the crystal’s resonant frequency. This makes the oscillator’s frequency stable over changes in temperature, supply, and aging, more so than with many other frequency-determining networks.

This setup is described as a crystal-controlled oscillator—the crystal controls the frequency. The other options describe different concepts: an LC tank oscillator relies on an inductance-capacitance network to set frequency, and a Hartley oscillator refers to a particular amplifier feedback topology. A vague “use of crystals” doesn’t name the circuit type.