Physics · AQA 7408 · Option E · Topic 3.13

Electronics

Option: semiconductor components, digital signals, op-amps, logic and communication systems.

  • 18 sub-topics
  • Taught in Year 13
  • 136 practice questions
  • 18 animated lessons
Practice questions (136) Lessons Worksheets All AQA Physics topics

What the specification says

Every sub-topic AQA can examine in this topic, with its reference number from the official specification. The Y12 and Y13 tags show when each sub-topic is usually taught.

  1. 3.13.1 Discrete semiconductor devices
  2. 3.13.1.1MOSFET (metal-oxide semiconducting field-effect transistor)Y13
  3. 3.13.1.2Zener diodeY13
  4. 3.13.1.3PhotodiodeY13
  5. 3.13.1.4Hall effect sensorY13
  6. 3.13.2 Analogue and digital signals
  7. 3.13.2.1Difference between analogue and digital signalsY13
  8. 3.13.3 Analogue signal processing
  9. 3.13.3.1LC resonance filtersY13
  10. 3.13.3.2The ideal operational amplifierY13
  11. 3.13.4 Operational amplifier in:
  12. 3.13.4.1Inverting amplifier configurationY13
  13. 3.13.4.2Non-inverting amplifier configurationY13
  14. 3.13.4.3Summing amplifier configurationY13
  15. 3.13.4.4Real operational amplifiersY13
  16. 3.13.5 Digital signal processing
  17. 3.13.5.1Combinational logicY13
  18. 3.13.5.2Sequential logicY13
  19. 3.13.5.3AstablesY13
  20. 3.13.6 Data communication systems
  21. 3.13.6.1Principles of communication systemsY13
  22. 3.13.6.2Transmission mediaY13
  23. 3.13.6.3Time-division multiplexingY13
  24. 3.13.6.4Amplitude (AM) and frequency modulation (FM) techniquesY13

Try 3 questions

Easy, medium and hard questions from this topic, each with a worked solutions and the mark for every step. All 136 questions in this topic, free, no account needed.

Electronics

Not needed for Year 12Easy

The gate of a MOSFET · Year 13 · 1 mark

  1. Why does the gate of a MOSFET draw almost no current?
    (1)

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  1. This lets a MOSFET be switched by a sensor or a logic gate that can supply only a tiny current.C: The gate is insulated from the channel, so its input resistance is extremely high

Total1

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Electronics

Not needed for Year 12Medium

The MOSFET · Year 13 · 3 marks

An n-channel enhancement MOSFET is used as a switch.
  1. (a)
    State the function of the gate, drain and source.
    (2)
  2. (b)
    Explain why a MOSFET draws almost no current from the input circuit.
    (1)
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Part (a)2 marks

  1. The gate p.d. controls the channel;
  2. current flows between drain and source.

Part (b)1 mark

  1. The gate is insulated from the channel, so its input resistance is very high.

Total3

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Electronics

Not needed for Year 12Hard

The Hall effect sensor · Year 13 · 4 marks

A semiconductor slice of thickness 0.5 mm carries a current of 0.02 A in a magnetic field of 0.25 T. The charge carrier density is 5×10215 \times 10^{21} m⁻³.
  1. (a)
    Explain why a Hall voltage is produced.
    (2)
  2. (b)
    Calculate the Hall voltage.
    (2)

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Part (a)2 marks

  1. The magnetic force deflects charge carriers to one side of the slice,
  2. until the electric field from the separated charge balances the magnetic force.

Part (b)2 marks

  1. VH=BInqtV_H = \frac{BI}{nqt}
  2. VH=0.0125 VV_H = 0.0125\ \mathrm{V}

Total4

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