Practise Standard circuit diagram symbols. 11 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
The circuit symbols you must recognise and draw, and how to read and draw circuit diagrams. Symbols come up in almost every electricity question: naming a component, completing a diagram, or drawing a circuit that could be used to take measurements.
Grade by grade
What you need to be able to do, from the first marks up to the top grade.
3
Name common components from their symbolsRecognise the cell, battery, switch, lamp, resistor, ammeter and voltmeter symbols.
4
Draw a simple series circuit correctlyUse a ruler, straight wires and the correct symbols, with no gaps in the loop.
4
Recognise diode, LED, fuse and variable resistorTell apart symbols that look alike, such as the diode and the LED, or the resistor and the fuse.
5
Recognise thermistor and LDR symbolsBoth start from the resistor box: the thermistor has a line with a flat tail through it, the LDR has two arrows pointing in.
5
Place ammeters and voltmeters correctlyDraw an ammeter in series with a component and a voltmeter in parallel across it.
6
Interpret circuit diagrams with junctionsWork out which components are in series and which are on parallel branches.
Notes
Supplies and switches
A cell is drawn as two parallel lines. The longer, thinner line is the positive terminal and the shorter, thicker line is the negative terminal.
A battery is two or more cells joined together. It is drawn as two or more cell symbols in a row (sometimes with a dashed line between them).
An open switch has a gap, so no current flows. A closed switch has no gap, so current can flow.
Components
Resistor: a plain rectangle (box). Variable resistor: the same box with a diagonal arrow through it, because its resistance can be changed.
Lamp: a circle with a cross inside it. Fuse: a small box with a line running through it from end to end.
Diode: a triangle pointing at a short bar. Current can only flow in the direction the triangle points.
LED (light-emitting diode): the diode symbol with two small arrows pointing away from it, because it gives out light.
LDR (light-dependent resistor): a resistor box inside a circle, with two arrows pointing towards it, because light falls on it.
Thermistor: a resistor box with a diagonal line through it that has a short flat tail at the bottom end.
Meters
Ammeter: a circle with A inside. It measures current and is always connected in series with the component.
Voltmeter: a circle with V inside. It measures potential difference and is always connected in parallel with (across) the component.
Drawing circuit diagrams
Use a ruler and a sharp pencil. Draw wires as straight lines with square corners.
Make sure the circuit is a complete loop, with no gaps except in an open switch.
Draw a dot at a junction, where wires join and the current splits or joins.
Keep each symbol the right shape: a line drawn through a resistor box turns it into a fuse.
Cheatsheet
Cell: long thin line = positive terminal, short thick line = negative terminal
Battery = two or more cells joined together
Diode: triangle and bar; current flows only in the direction the triangle points
LED: diode symbol + arrows pointing OUT (light comes out)
LDR: resistor box in a circle + arrows pointing IN (light goes in)
Thermistor: resistor box + diagonal line with a flat tail
Variable resistor: resistor box + diagonal arrow
Fuse: box with a line through it end to end
Ammeter (A) in series; voltmeter (V) in parallel
How to answer each type of question
Name the component from its symbol
1 mark each3
Start with the basic shape: box (resistor family), circle (lamp or meter) or triangle and bar (diode family).
Look for the extra detail: an arrow through it, arrows in or out, a cross, a letter or a tailed line.
Give the full name, e.g. 'light-dependent resistor' or 'LDR', not just 'resistor'.
Example. A student describes three circuit symbols. (a) A circle with a cross inside it. (b) A rectangle with a diagonal arrow through it. (c) A triangle pointing at a short bar, with two small arrows pointing away from it. Name the component that each symbol represents.
Draw a circuit diagram that could be used to take measurements
2 to 3 marks4
Put the supply, switch, component and ammeter in one series loop.
Connect the voltmeter in parallel across the component only, not across the supply.
Use correct symbols, a ruler and no gaps in the circuit.
Example. A student wants to measure the current through a lamp and the potential difference across the lamp. She has a battery, a lamp, a switch, an ammeter and a voltmeter. Draw a circuit diagram she could use.
Show the model answer
Battery, switch, lamp and ammeter all connected in one series loop (1). Voltmeter connected in parallel across the lamp only (1). All symbols correct (1).
Identify and correct a mistake in a circuit
2 marks5
Check that each meter is in the right place: ammeter in series, voltmeter in parallel.
Check for gaps, open switches and components drawn the wrong way round (e.g. a diode pointing against the current).
Say what is wrong AND how to put it right.
Example. A student wants to measure the potential difference across a resistor. He connects the cell, the resistor and the voltmeter one after another in a single loop. Explain what is wrong with his circuit and how he should correct it.
Show the model answer
The voltmeter is connected in series with the resistor, but it must be connected in parallel with (across) the resistor (1). He should connect the resistor directly to the cell in a loop and connect the voltmeter's two leads to the two ends of the resistor (1).
Shortcuts and memory tricks
Arrows OUT = light OUT (LED). Arrows IN = light IN (LDR).
Ammeters go IN the loop (series); voltmeters go AROUND the component (parallel).
Long line = plus: you need the longer line to make a + sign.
The resistor family all start with the same box: add an arrow for variable, a tailed line for thermistor, a circle and arrows in for LDR, a line through it for fuse.
Where marks are lost
Mixing up the LED and the LDR: check which way the arrows point.
Drawing the voltmeter in series or the ammeter in parallel.
Leaving gaps in the circuit, or drawing wires freehand so they run through symbols.
Drawing a diode the wrong way round, so it blocks the current.
Confusing the fuse (line through the box) with the resistor (empty box).
Exam technique
Use a ruler and a sharp pencil for circuit diagrams, and check every symbol before moving on.
If a question says 'draw a circuit that could be used to...', include every meter it mentions and put each one in the right place.
The mark is for the correct symbol. A label does not rescue a wrong symbol, so draw it carefully.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy3 marks
(a) Which component allows current to flow in one direction only, and also emits light? Tick (✓) one box.[1]
Diode
LED
Resistor
Thermistor
(b) Which two components have a resistance that changes with the surrounding conditions (light or temperature)? Tick (✓) two boxes.[2]
LDR
Fuse
Thermistor
Switch
Show the answer and mark scheme
(a)Answer: LED
(b)Answer: LDR; Thermistor
Question 2Medium4 marks
A technician describes a circuit: a battery is connected in series with a switch, a fuse, a resistor and an LED. The LED is connected so that it lights when the switch is closed.
Draw a circuit diagram for this circuit, using the correct circuit symbols. Draw the battery with its positive terminal at the top.[4]
Show the answer and mark scheme
Answer: A single series loop containing a battery (positive terminal at the top), a switch, a fuse, a resistor and an LED, with the LED drawn so that conventional current from the positive terminal flows through it in its forward direction.
battery drawn with the correct symbol (two or more cells, each a long and a short line), with its positive terminal (long line) at the top
switch and fuse drawn with the correct symbols, in series with the battery in a single complete loop
resistor drawn as a rectangle, in series with the LED
LED drawn with the correct symbol (diode symbol with two arrows pointing away), pointing in the direction of the conventional current from the positive terminal
Question 3Hard6 marks
A student wants to build a warning circuit for a motor that may overheat. The circuit contains a battery, a switch, a thermistor, a fixed resistor and an LED, all connected in series. The LED should become noticeably brighter as the temperature of the thermistor increases.
Draw a circuit diagram for this circuit, using the correct circuit symbols, and explain how the circuit works and the purpose of each component.[6]
Show the answer and mark scheme
Answer: A series loop of battery, switch, thermistor, fixed resistor and LED, drawn with correct symbols and the LED pointing in the direction of the conventional current; the switch turns the circuit on and off; the fixed resistor limits the current to protect the LED; as the thermistor warms its resistance falls, so the current rises and the LED gets brighter.
the battery, switch, thermistor, fixed resistor and LED are drawn in one series loop
correct symbols are used: battery (two or more cells), switch, thermistor (resistor box with a bent diagonal line), fixed resistor (rectangle) and LED (diode symbol with two arrows pointing away)
the LED is drawn the right way round, so that conventional current from the positive terminal flows through it in its forward direction
the switch allows the circuit to be turned on and off
the fixed resistor limits the current, so the LED is not damaged when the thermistor's resistance is low
as the temperature of the thermistor increases, its resistance decreases
so the total resistance of the circuit decreases and the current increases (for the same battery potential difference)
the larger current makes the LED brighter, warning that the motor is getting hot
Marked with levels of response: the full level descriptors are in the app.