Standard Circuit Symbols
Learn Standard Circuit Symbols for GCSE Physics with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Circuit diagrams use standard symbols for cells, switches, resistors, lamps, diodes and meters so any circuit can be drawn and read.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Circuit diagrams use standard symbols so that any physicist can read them, regardless of language. Learning them precisely is necessary because a wrong symbol changes the meaning of the circuit.
The symbols required are cell, battery, switch open and closed, lamp, fuse, resistor, variable resistor, ammeter, voltmeter, LED, LDR, thermistor and diode.
Two distinctions cause most errors. A cell is a single unit with one long and one short line; a battery is two or more cells. And an ammeter is drawn in series with the component it measures, whereas a voltmeter is drawn in parallel across it.
Revision notes
The key symbols
A cell is one long line and one short line. A battery is two or more cells joined.
A lamp is a circle with a cross. A resistor is a rectangle. A variable resistor is a rectangle with an arrow through it. A fuse is a rectangle with a line through it.
Meters
An ammeter is a circle containing the letter A, connected in series with the component.
A voltmeter is a circle containing the letter V, connected in parallel across the component. Getting these the wrong way round is the most common error in circuit diagrams.
Components with special behaviour
A diode allows current in one direction only, shown as a triangle against a line.
An LED is a diode that emits light. An LDR has a resistance that falls as light intensity increases. A thermistor has a resistance that falls as temperature increases.
Key points
- Standard symbols are used in all circuit diagrams.
- A cell is one long and one short line.
- A battery is two or more cells.
- An ammeter is connected in series.
- A voltmeter is connected in parallel.
- A diode allows current in one direction only.
Worked examples
Example 1
State how an ammeter and a voltmeter should be connected in a circuit. [2 marks]
Model answer
An ammeter is connected in series with the component whose current is being measured (1 mark). A voltmeter is connected in parallel across the component whose potential difference is being measured (1 mark).
Example 2
Describe the difference between the symbol for a cell and the symbol for a battery. [2 marks]
Model answer
A cell is drawn as a single pair of lines, one long and one short (1 mark). A battery is drawn as two or more cells joined together (1 mark).
Example 3
State the function of a diode in a circuit. [1 mark]
Model answer
A diode allows current to flow in one direction only (1 mark).
Common mistakes
Connecting a voltmeter in series.
It must be in parallel across the component.
Confusing cell and battery symbols.
A battery is two or more cells.
Drawing the diode the wrong way round.
The triangle points in the direction current is allowed to flow.
Confusing LDR and thermistor.
An LDR responds to light; a thermistor responds to temperature.
Exam tips
- Learn all the required symbols precisely.
- Remember ammeter in series, voltmeter in parallel.
- Use a ruler when drawing circuit diagrams.
- Check the diode direction against the current direction.
Key terms
- Cell
- A single source of potential difference.
- Battery
- Two or more cells connected together.
- Ammeter
- A meter measuring current, connected in series.
- Voltmeter
- A meter measuring potential difference, connected in parallel.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.