OVERVIEW

In Chapter 9 we found that RLC circuits possess the distinctive ability to provide natural responses of the oscillatory type. This ability stems from the flow of energy back and forth between the capacitance and the inductance. It is not surprising that RLC circuits also exhibit a distinctive ac behavior. This stems from the fact that inductance and capacitance have dual ac characteristics: The inductive reactance X _L = ? L is positive and is directly proportional to ?, whereas the capacitive reactance X _C = ?1/ ? C is negative and inversely proportional to ?. Depending on frequency, X _L or X _C may dominate, or the two reactances may cancel each other out, making a series LC combination act as a short circuit, and a parallel LC combination as an open. This cancellation provides the basis for a form of resonance known as unity power-factor resonance to reflect the fact that if the series or parallel LC combination is embedded in a resistive circuit, at resonance all voltages and currents in the circuit will be in phase with the applied source, thus yielding a power factor of unity.

Another distinguishing feature of resonant RLC circuits is the ability to provide a form of signal magnification known as resonance signal rise, a phenomenon not found in other passive ac circuits, where all...