Transistor Power Dissipation: The power dissipation in a transistor is the product of which electrical quantities?
Electronics and Communication Engineering
Electronic Devices and Circuits
Difficulty: Easy
Choose an option
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Aemitter current and emitter-to-base voltage
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Bemitter current and collector-to-emitter voltage
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Ccollector current and collector-to-emitter voltage
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Dnone of the above
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Ebase current and base-to-emitter voltage
Answer
Correct Answer: collector current and collector-to-emitter voltage
Explanation
Introduction / Context:Power dissipation is critical in transistor operation. Excessive dissipation can overheat the device and cause failure. Designers must know which current-voltage product determines device heating.
Given Data / Assumptions:
- Device: BJT.
- Quantities of interest: IC, VCE, IE, VBE.
Concept / Approach:
Instantaneous power dissipated at collector junction = IC * VCE. This dominates device thermal load.
Step-by-Step Solution:
Step 1: P = V * I for junction.Step 2: In BJT, controlling terminal is collector-emitter.Step 3: Therefore P = IC * VCE.Verification / Alternative check:
Datasheets specify maximum power rating as IC * VCE product, confirming definition.
Why Other Options Are Wrong:
- IE * VBE: negligible compared to IC * VCE.
- IE * VCE: incorrect combination.
- None of the above: false, correct defined.
Common Pitfalls:
- Using base current × base voltage instead.
Final Answer:
collector current and collector-to-emitter voltage