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⚛️ Physics  ·  Semiconductor Electronics  ·  NEET & JEE

In a CMOS circuit, the power consumption P<sub>dynamic</sub> =

Answer: C × V² × f (capacitance × supply voltage squared × frequency).

  • A I × V, the basic instantaneous power formula with no switching-frequency term
  • B C × V² × f (capacitance × supply voltage squared × frequency)
  • C V²/R, the static power dissipation formula for a simple resistor
  • D I² × R, the static power dissipation formula in terms of current

Correct answer: B. C × V² × f (capacitance × supply voltage squared × frequency)

Explanation: CMOS dynamic power: P = alpha × C<sub>L</sub> × V<sub>DD</sub>² × f. Charging/discharging load capacitance each switching event. Key driver of CPU power limits.

Conductorconduction bandvalence bandbands overlapSemiconductorconduction bandvalence bandsmall gap (~1 eV)Insulatorconduction bandvalence bandlarge gap(> 3 eV)

Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.

Concept context

Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.

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