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

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:

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