Chapter 3. Impedance and Electrical Models

1. The important feature of the frequency domain is that the only waveforms that can exist are sine waves. We can only describe the behavior of ideal circuit elements in the frequency domain by how they interact with sine waves: sine waves of current and sine waves of voltage. These sine waves have three and only three features: the frequency, the amplitude, and the phase associated with each wave.

2.It is important to keep straight that for an ideal capacitor or inductor, even though its value of capacitance and inductance is absolutely constant with frequency, its impedance will vary with frequency.