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Core · Practice questions · Circuit symbols

Symbols and what they do.

Six original Cambridge-style questions on circuit symbols: naming components, the rules each symbol carries, reading a simple diagram, and recalling what each component does.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
What to keep in mind

Each symbol carries a rule.

01
Recall
[3 marks]

Name the component represented by each of these symbols: (a) a circle with the letter A, (b) a circle with a cross inside, (c) a triangle touching a straight bar.

  • (a) an ammeter. ✓
  • (b) a lamp. ✓
  • (c) a diode. ✓
02
Recall
[2 marks]

State how an ammeter and a voltmeter should each be connected into a circuit.

  • An ammeter is connected in series. ✓
  • A voltmeter is connected in parallel (across the component). ✓
03
Application
[2 marks]

Describe how a thermistor and a light-dependent resistor each respond to a change in their surroundings.

  • A thermistor: its resistance falls as its temperature rises. ✓
  • A light-dependent resistor: its resistance falls as the light gets brighter. ✓
04
Application
[2 marks]

A student wants to draw a circuit with a cell, a switch and a lamp connected one after another. Describe the diagram, and state what the long line and the short line on the cell represent.

  • A single loop with the cell, switch and lamp joined in series by straight lines (wires). ✓
  • The long line is the positive terminal and the short line is the negative terminal. ✓
05
Analysis
[2 marks]

State the purpose of a fuse in a circuit, and describe what happens to it if the current becomes too large.

  • A fuse protects the circuit from too large a current. ✓
  • If the current is too large, the fuse wire melts and breaks the circuit, stopping the current. ✓
06
Analysis
[2 marks]

A diode is placed in a circuit so that its triangle points from the positive terminal toward the lamp. State whether the lamp lights, and explain. Then state what happens if the diode is reversed.

  • The lamp lights, because the diode is forward (current can pass in the direction the triangle points). ✓
  • If the diode is reversed, it blocks the current and the lamp does not light. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.