Norton’s equivalent current (IN): Is it defined as the open-circuit current between two terminals, or the short-circuit current?
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AFalse
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BTrue
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CIt is the average of open- and short-circuit currents
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DIt equals the Thevenin voltage divided by the shorted resistance
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EIt is measured with the load at rated power
Answer
Correct Answer: False
Explanation
Introduction / Context:Norton and Thevenin equivalents are dual representations of a linear two-terminal network. Correctly identifying Norton’s current prevents mistakes when transforming sources or characterizing loads.
Given Data / Assumptions:
- Linear, bilateral network with independent/dependent sources and resistors.
- Two terminals under test for equivalent replacement.
- Standard definitions of open-circuit and short-circuit measurements.
Concept / Approach:
Norton’s current IN is the short-circuit current between the two terminals (with the terminals shorted). Thevenin’s voltage VTH is the open-circuit voltage between the two terminals. The Norton/Thevenin resistance is the same: RN = RTH (under appropriate deactivation rules).
Step-by-Step Solution:
Determine VTH: measure or compute the open-circuit voltage (no load connected).Determine IN: short the terminals and compute the resulting current through the short; IN = ISC.Relate the two: VTH = IN * RTH, and RTH = RN.Hence, IN is not an open-circuit current; it is the short-circuit current.Verification / Alternative check:
By transformation: if you know VTH and RTH, the equivalent Norton current is IN = VTH / RTH, which numerically equals the short-circuit current you would measure directly.
Why Other Options Are Wrong:
- Calling IN an open-circuit current confuses it with VTH definition.
- No averaging is involved; it is strictly the short-circuit current.
- The statement “divided by the shorted resistance” is unclear; the correct relation is IN = VTH / RTH.
- Rated power of the load is irrelevant to the definition.
Common Pitfalls:
Using open-circuit current (which is zero in resistive networks) instead of short-circuit current for Norton calculations, leading to erroneous equivalences.
Final Answer:
False