Exam-style question
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Which configuration has a voltage gain of 1 + R2/R1?.
- A.Inverting amplifier has a gain of -R2/R1
- B.Non‑inverting amplifier has a gain of 1 + R2/R1
- C.Both amplifiers have a gain of 1 + R2/R1
- D.Neither amplifier has a gain of 1 + R2/R1
Model answer
What a good answer should say
- Non‑inverting amplifier has a gain of 1 + R2/R1
Explanation
Why this works
Define both: Inverting amplifiers give a gain of -R2/R1; non‑inverting amplifiers give a gain of 1 + R2/R1. Identify key difference: the presence of the +1 term.
Explain when each applies: use the inverting formula when the output must be inverted; use the non‑inverting formula when the output should be in phase. Conclude: the correct configuration is the non‑inverting amplifier.
Common mistake
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