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CAIE A-Level Physics Circuit Symbols

Practise recognising CAIE A-Level Physics circuit symbols and using component behaviour, polarity and current paths to complete or interpret diagrams.

Syllabus
2028–2030
Course
Physics 9702
Level
A2

Exam points

  • identify and interpret official circuit symbols for components and output devices
  • draw circuit diagrams with correct component symbols, polarity and connections
  • relate circuit-symbol choices to current, potential difference, resistance and component behaviour

Covered syllabus points

C.1-Circuit symbols used in examination papersC.2-Drawing and interpreting circuit diagrams

Circuit symbols question 1

[Maximum number: 3]

A circuit incorporating an ideal operational amplifier (op-amp) is shown in Fig. 7.1.

Fig. 7.1

Fig. 7.1

The variation with temperature θ\theta of the resistance RTR_{\mathrm{T}} of the thermistor is shown in Fig. 7.2.

Fig. 7.2

Fig. 7.2

The output of the op-amp is to be displayed using two light-emitting diodes (LEDs) labelled G and B.
When the temperature of the thermistor is below 4.0∘C4.0^{\circ} \mathrm{C}, only the LED labelled G emits light. The LED labelled B emits light only when the temperature of the thermistor is above 4.0∘C4.0^{\circ} \mathrm{C}.

On Fig. 7.1, draw and label the symbols for the two LEDs.

Circuit symbols question 2

[Maximum number: 2]

An ideal op-amp is incorporated into the circuit of Fig. 8.1.

Fig. 8.1

Fig. 8.1

On Fig. 8.1, draw the symbol for a light-emitting diode (LED), connected at the output of the circuit, such that it emits light when the resistance of the thermistor is less than RTR_{\mathrm{T}}.

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