DC and AC Circuit Analysis Flashcards

What is the resonant frequency of a series RLC circuit with L = 10 mH and C = 10 μF?

Answer: 503 Hz

f₀ = 1/(2π√LC) = 1/(2π√(0.01 × 10⁻⁵)) ≈ 503 Hz.

In a parallel RLC circuit, resonance occurs when the circuit exhibits:

Answer: Maximum impedance and minimum current

At parallel resonance, the susceptances of L and C cancel, yielding maximum impedance and minimum line current drawn from the source.

Applying the superposition theorem, what must be done with independent sources not under consideration?

Answer: Voltage sources are short-circuited; current sources are open-circuited

Superposition requires deactivating all other independent sources: replace voltage sources with short circuits and current sources with open circuits.

What is the reactance of a 100 μF capacitor at 60 Hz?

Answer: 26.5 Ω

Xc = 1/(2πfC) = 1/(2π × 60 × 100×10⁻⁶) ≈ 26.5 Ω.

In a DC circuit, if two resistors R1 = 4 Ω and R2 = 6 Ω are connected in parallel, what is the equivalent resistance?

Answer: 2.4 Ω

Req = (R1 × R2)/(R1 + R2) = (4 × 6)/(4 + 6) = 24/10 = 2.4 Ω.

What is reactive power measured in?

Answer: VAR (volt-ampere reactive)

Reactive power, Q, is the power stored and released by reactive elements (inductors/capacitors) and is measured in volt-amperes reactive (VAR).

In nodal analysis, what is chosen as the reference (datum) node?

Answer: The node with the most connections (often ground)

The reference node, typically ground (0 V), is usually chosen as the node with the most branch connections to simplify the system of equations.