Power regulation taxonomy: In a series dissipative voltage regulator, a pass element (such as a BJT or MOSFET) operates in its linear region to drop excess voltage and maintain a steady output. To which regulator class does this topology belong?
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Alinear regulator
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Bswitching regulator
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Cshunt regulator
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Ddc-to-dc converter
Answer
Correct Answer: linear regulator
Explanation
Introduction:Voltage regulators are categorized by how the pass device controls energy flow. Recognizing whether a topology is linear or switching is essential for predicting efficiency, noise, and thermal behavior.
Given Data / Assumptions:
- Series pass device drops voltage continuously.
- Operation is in the linear (ohmic) region, not as a saturated switch.
- Goal is a stable DC output with minimal ripple.
Concept / Approach:A series dissipative regulator regulates by varying the pass element's resistance so that Vout remains constant despite Vin or load changes. Energy is burned as heat across the pass device, a hallmark of linear regulation. In contrast, switching regulators modulate a switch and use inductors/capacitors to transfer energy at high efficiency.
Step-by-Step Solution:1) Identify pass element behavior: continuously variable conduction, not on/off switching.2) Recognize energy path: excess voltage * load current is dissipated as heat.3) Classify accordingly: that is the definition of a linear regulator.4) Distinguish from switching types that pulse energy and filter it.
Verification / Alternative check:Efficiency trend confirms classification: linear regulators typically show efficiency ≈ Vout/Vin, while switching regulators can exceed that in many cases, reinforcing that a dissipative series pass design is linear.
Why Other Options Are Wrong:Switching regulator: relies on high-frequency switching; not linear operation.Shunt regulator: uses a variable shunt path to ground; not a series pass element.DC-to-DC converter: umbrella term that often implies a switching topology; the specific class here is linear.
Common Pitfalls:Assuming all regulators with a transistor are switching; operating region (linear vs switching) is the key differentiator.
Final Answer:linear regulator