Circuit Theory and Analysis Flashcards

In a series RLC circuit at resonance, the impedance is equal to:

Answer: The resistance R only

At resonance XL equals XC and they cancel, leaving only the resistance R as the total impedance.

Thevenin's theorem states that any linear circuit can be replaced by:

Answer: A voltage source in series with an impedance

Thevenin's theorem replaces a complex linear network with a single voltage source (Vth) in series with a single impedance (Zth).

The time constant of an RC circuit is defined as the time required for the capacitor voltage to reach approximately:

Answer: 63.2% of its final value

One time constant (τ = RC) corresponds to the voltage reaching 63.2% (1 - 1/e) of its final value.

Which network theorem is the dual of Thevenin's theorem?

Answer: Norton's theorem

Norton's theorem is the dual of Thevenin's theorem, replacing a network with a current source in parallel with an impedance.

In a parallel RLC circuit, resonance occurs when the source current is:

Answer: At minimum value

At parallel resonance the tank circuit impedance is maximum, so the source current drawn is at its minimum value.

The superposition theorem applies only to circuits that are:

Answer: Linear and bilateral

Superposition requires linearity so that contributions from each independent source can be added algebraically.

If two capacitors C1 = 4 µF and C2 = 12 µF are connected in series, the total capacitance is:

Answer: 3 µF

Series capacitance: 1/CT = 1/4 + 1/12 = 4/12, so CT = 3 µF.