In superposition theorem, when we consider the effect of one voltage source, all the other voltage s

Question

In superposition theorem, when we consider the effect of one voltage source, all the other voltage sources are _________

Examoogle · Accepted Answer

Shorted

Explanation: The superposition theorem states that in a linear, bilateral network with multiple sources, the total current or voltage in any element is the algebraic sum of the individual currents or voltages produced by each source acting independently. When considering the effect of one source, all other independent voltage sources are replaced by their internal resistance, which is zero for an ideal voltage source (short circuit).

Working Principle: In superposition, independent sources must be 'deactivated' to isolate the effect of a single source. An ideal voltage source has an internal impedance of $0 \Omega$, meaning replacing it with a short circuit (a wire with zero resistance) maintains the same potential difference ($V=0$) across its original terminals. Conversely, independent current sources are replaced by an open circuit (infinite impedance) because they force current to be zero.

Key Formulas: $V_{total} = V_1 + V_2 + ... + V_n$; $R_{int(ideal\_voltage)} = 0 \Omega$

Key Points: Applicable only to linear circuits.; Dependent sources must remain in the circuit during analysis.; Power calculations cannot be done using superposition because power is a non-linear function ($P = I^2 R$).; Voltage sources are shorted, current sources are opened.

Advantages: Simplifies complex circuits with many independent sources.; Avoids the need to solve large systems of simultaneous equations.

Disadvantages: Inefficient if the circuit has only one source.; Cannot be used for power calculations.

Applications: Network analysis in electronics.; Power system steady-state analysis.

Additional Info: The internal resistance of an ideal voltage source is $0 \Omega$.. Option B (Opened) is the procedure for independent current sources, not voltage sources.

Answer: A is correct — In superposition theorem, all independent voltage sources are replaced by short circuits when calculating the contribution of a single source.

Exam Tip: Always remember the mnemonic: 'Voltage sources are Shorted (VS), Current sources are Opened (CO)'. This is a frequent point of confusion in competitive exams.

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