AC Circuits Study Guide

For the test over ac circuits, you should know:

• What is reactance in a circuit (capacitive and inductive)? Upon what parameter does it depend? Is power consumed in reactance?
• What is impedance in an ac circuit?
• What is the effective value of current or voltage? What is another name for it? How does it relate to the maximum value?
• How is power calculated in an ac circuit? When does power equal current squared times the resistance, as in a dc circuit?
• In a purely resistive circuit, how are the graphs of current, voltage, and power related?
• What is the phase angle for a purely inductive circuit? For a purely capacitive circuit? For a circuit with inductance and resistance? For capacitance and resistance?
• What is the power factor in terms of the phase angle and the circuit voltages? What does it tell you about the circuit?
• When does resonance occur in an LRC circuit? How does the impedance compare with the resistance? What is the phase relationship between voltage and current at resonance? What about current amplitude?
• What is the Q of a resonant circuit?

And be able to:

• Calculate the maximum or effective value of current or voltage.
• Calculate the total reactance of a circuit.
• Calculate the inductive and capacitive reactance, impedance, phase angle, circuit current, voltage drops across resistor, capacitor, and inductor
• Draw a circuit diagram and impedance diagram for an LRC circuit.
• Calculate the resonant frequency of an LC circuit