What is the equivalent circuit of a quartz crystal?
Series RLC in parallel with a shunt C representing electrode and stray capacitance✓Correct answer
Parallel RLC, where C is the parallel combination of resonance capacitance of the crystal and electrode and stray capacitance
Series RLC, where C is the parallel combination of resonance capacitance of the crystal and electrode and stray capacitance
Parallel RLC, where C is the series combination of resonance capacitance of the crystal and electrode and stray capacitance
Explanation
The mechanical resonance of the quartz plate appears electrically as a series RLC branch, the motional arm, while the metal electrodes and wiring add a capacitance in parallel with it. That shunt capacitance is why a crystal has both a series resonance and a slightly higher parallel resonance rather than a single resonant frequency.