Multiple sources in one network: Do some circuit topologies legitimately require more than one independent voltage or current source?

Electrical Engineering Circuit Theorems and Conversions Difficulty: Easy
Choose an option
  • A
    True
  • B
    False
  • C
    Only in AC systems, never in DC
  • D
    Only for testing, not for real designs
  • E
    Only if sources are identical and in series

Answer

Correct Answer: True

Explanation

Introduction / Context:Real systems often combine multiple sources to meet performance needs: biasing and signal injection in amplifiers, dual rails in op-amp circuits, battery + photovoltaic hybrids, or mixed current/voltage excitations in measurement setups.

Given Data / Assumptions:

  • Linear or nonlinear networks may include several independent sources.
  • Sources can be of different types (voltage or current) and polarities.
  • Operation is steady-state for analysis clarity.

Concept / Approach:

Superposition applies to linear networks: the response to multiple independent sources equals the algebraic sum of the responses to each source acting alone (with others deactivated per type). Multiple sources enable bias + signal, redundancy, or energy sharing among subsystems.

Step-by-Step Solution:

Identify the purpose of each source (e.g., DC bias, AC signal, reference, current excitation).Analyze via superposition for linear circuits: zero-out voltage sources to their internal resistance and current sources to their internal resistance.Combine contributions to find voltages/currents of interest.Validate operating points and power flows for safety and performance.

Verification / Alternative check:

Common designs—op-amp amplifiers with +V and −V rails, RF mixers with LO + RF sources, LED drivers mixing a current source with voltage-limited supply—demonstrate legitimate multiple-source usage.

Why Other Options Are Wrong:

  • DC systems frequently use multiple sources (e.g., dual batteries, bias plus signal).
  • Use is not limited to lab testing; it is standard practice in production designs.
  • Sources need not be identical nor strictly series-connected; topology depends on the function.

Common Pitfalls:

Failing to check interaction between sources, such as back-driving or circulating currents. Use diodes, OR-ing controllers, or proper isolation as needed.

Final Answer:

True

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