## AC Circuit

### Instructions

The first graph you see shows the voltage across each
component as a function of time. The black curve is the
voltage coming from the power supply (note that this
does not change amplitude). The blue curve is the voltage
across the resistor - it is directly proportional to
the current, so it shows the phase relationship between
the power supply voltage and the current.

The red and
green curves show the voltage across the capacitor and
the inductor, respectively. Note that the voltage across the
inductor always leads the current in the circuit by 90 degrees, no
matter what the frequency. Similarly, the voltage across
the capacitor is always 90 degrees behind the current.

Modify the frequency, and note in particular what happens
at the resonance frequency, when the black and blue curves
are in phase.

You can view the other graph, showing the rms current in
the circuit, by clicking on the box marked "Voltage". Again,
note in particular what happens at the resonance frequency.

By placing the mouse over any component (the inductor, for
instance) you can see its value, the voltage across it, and
the phase angle of the voltage across it (relative to the
voltage of the AC source).

### Acknowledgements

This simulation is based on a physlet by Wolfgang Christian, part of the
physlets page
at Davidson College.