DC Circuit Analysis & Theory Flashcards

Thévenin's theorem states that any linear DC network can be reduced to:

Answer: A single voltage source in series with a resistance

Thévenin's theorem replaces any linear two-terminal network with an equivalent V_th in series with R_th.

To find the Thévenin resistance (R_th) of a circuit, you should:

Answer: Short all current sources and open all voltage sources, then measure resistance at the terminals

Independent voltage sources are shorted and independent current sources are opened when deactivating sources to find R_th.

The superposition theorem applies only to circuits that are:

Answer: Linear bilateral

Superposition requires linearity and bilaterality so that each source's contribution can be analyzed independently and summed.

Using superposition, you analyze a two-source circuit and find source A contributes 4 A and source B contributes −1 A through a branch. The actual current is:

Answer: 3 A

Superposition sums all individual contributions: 4 + (−1) = 3 A.

Norton's equivalent circuit consists of:

Answer: A current source in parallel with a resistor

The Norton equivalent replaces a network with I_N (short-circuit current) in parallel with R_N (= R_th).

A circuit has V_th = 10 V and R_th = 5 Ω. If a 5 Ω load is connected, the load current is:

Answer: 1 A

I = V_th / (R_th + R_L) = 10 / (5 + 5) = 1 A.

Maximum power is transferred from a source to a load when the load resistance equals:

Answer: The source (Thévenin) resistance

The Maximum Power Transfer theorem states P_max occurs when R_L = R_th.