Combined resonance plots of a LCR (inductance-capacitance-resistance) circuit for different values of resistance and at different values of inductance and capacitance.

This Demonstration shows the variation of current with frequency in a circuit with the a resistor , capacitor and an inductor in series. The current amplitude is given by the equation, current ∝

,

Snapshot 1: The variation of current with frequency for the lowest value of resistance. The current amplitude is large and the resonance curve is sharp.

Snapshot 2: The variation of current with frequency for different values of resistance is seen. The current amplitude peaks are large for smaller values of resistances and successively smaller for higher values of the resistance. Higher values of resistances show resonance curves which are broader

Snapshot 3: The resonant frequency or the peaks of the current amplitude curves shift with change of either the capacitance or inductance values