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Circuit Quest
Mission 02
Step 1/7
Circuit Quest
20 minstarter

MISSION 02 · BASIC ELECTRONICS

See How Resistance Changes Light

Jump to the build step

Can you create three visible brightness levels using only resistors?

1 · Close the Loop

Your new skill: Compare resistance without changing every part.

Revisit the skill you will reuse: Previous main-path mission

Meet the parts

Match the names to your parts before you build. New parts appear when you first need them. You can point, say the name or show a grown-up.

Battery and holder

A battery supplies energy that can make a light glow or a motor turn. A holder keeps its connections in place.

Spot it and try it

Look for: Find the + and - marks and the matching holder or snap connector.

Before using it: Use only the supply named in this mission. Never join + straight to -; disconnect before rewiring.

Your turn: With power disconnected, trace the path from + through the parts and back to -.

Breadboard

This reusable building board joins some holes with hidden metal strips, so we can connect parts without soldering.

Spot it and try it

Look for: Find the centre gap, row numbers and power rails. The gap separates the two halves.

Before using it: Five holes in one numbered strip usually join; the strip across the gap does not. Some power rails have a break. Match your board diagram.

Your turn: Point to two holes on the same connected strip, then two that are separated by the gap.

Jumper wire and clip lead

A wire makes an electrical connection between two points. A clip lead grips a terminal.

Spot it and try it

Look for: Jumpers have small plug ends; clip leads have metal jaws. Colour helps us track a connection.

Before using it: Colour does not change a wire's job. Check both ends and keep bare metal away from other terminals.

Your turn: Follow one wire from start to finish and name what it joins.

Resistor

A resistor limits current in a path. Beside our LED it helps protect the light from too much current. Its resistance is measured in ohms.

Spot it and try it

Look for: Look for a small body with two legs and coloured bands; match its labelled value to the mission.

Before using it: A resistor can face either way. Values such as 1 kΩ and 10 kΩ are different: k means one thousand. Keep the specified value.

Your turn: Point to the resistor in the LED path. Explain why replacing it with a plain wire is not our test.

LED or light emitting diode

An LED turns electrical energy into light and works in one direction. We use it to show what a circuit is doing.

Spot it and try it

Look for: An untrimmed ordinary LED often has a longer anode leg and a shorter cathode leg. A flat rim often marks the cathode.

Before using it: Confirm polarity with the part card if legs are trimmed. Use the mission's resistor in series; never connect an LED straight across the battery.

Your turn: With power off, identify the two legs and point to its protective resistor.

Meet the parts for See How Resistance Changes Light

A video demonstration will appear here when it is ready. You can follow the written step now.

Read the video instructions

Before we build, match these names to the parts in front of you. Battery and holder. A battery supplies energy that can make a light glow or a motor turn. A holder keeps its connections in place. Find the + and - marks and the matching holder or snap connector. Use only the supply named in this mission. Never join + straight to -; disconnect before rewiring. Breadboard. This reusable building board joins some holes with hidden metal strips, so we can connect parts without soldering. Find the centre gap, row numbers and power rails. The gap separates the two halves. Five holes in one numbered strip usually join; the strip across the gap does not. Some power rails have a break. Match your board diagram. Jumper wire and clip lead. A wire makes an electrical connection between two points. A clip lead grips a terminal. Jumpers have small plug ends; clip leads have metal jaws. Colour helps us track a connection. Colour does not change a wire's job. Check both ends and keep bare metal away from other terminals. Resistor. A resistor limits current in a path. Beside our LED it helps protect the light from too much current. Its resistance is measured in ohms. Look for a small body with two legs and coloured bands; match its labelled value to the mission. A resistor can face either way. Values such as 1 kΩ and 10 kΩ are different: k means one thousand. Keep the specified value. LED or light emitting diode. An LED turns electrical energy into light and works in one direction. We use it to show what a circuit is doing. An untrimmed ordinary LED often has a longer anode leg and a shorter cathode leg. A flat rim often marks the cathode. Confirm polarity with the part card if legs are trimmed. Use the mission's resistor in series; never connect an LED straight across the battery. Pause and point to the part that will do the main job in this mission. If it is missing or looks different, ask a grown-up before building.

WHAT YOU'LL USE

Match these to your kit

1 x 2.2k resistor1 x 2.7k resistorBreadboard and jumper wires

Reuse from an earlier mission

Working Mission 1 circuit

Kit list: match the named parts to your box and its component cards. Home list: gather these before starting; some may also be supplied in your kit. Reuse components between missions. Stop and ask a grown-up if an essential part or label is missing.

BEFORE YOU BUILD

Use the same LED, battery and room lighting for every test. Power off before changing resistors.

YOUR REWARD

+50 XPMission completion

PREDICT BEFORE YOU BEGIN

What do you think will happen? Say it, point to it or draw it. Then test your idea.

YOUR CHALLENGE

How does resistance affect the same light? Compare three setups and record whether the difference is visible.

NEW POWER-UP

Compare resistance without changing every part.

You already know: you can build a protected LED circuit New power-up: fair testing and comparing resistance This prepares you for: using two controls in one path

Adult help: Usually not needed
Open diagrams and build references
How a breadboard connects insideBreadboard connection groupsWithin one numbered row A to E are connected, and F to J are connected separately. The centre gap separates them. Adjacent numbered rows are separate. Rail breaks vary; check your supplied board.151617ABCDEFGHIJCentre gap: no internal connection across

Each coloured strip is one connected group. Different numbered rows stay separate. This explains the board; use the mission’s exact connection reference for component positions. Check rail breaks on your supplied board.

Check the connection map

CONNECTION MAP

Build the electrical path before you test.

Keep power disconnected while changing connections.
JoinConnectWhy it matters
1Every test: 9V red -> + rail; black -> - railKeeps the power source unchanged for a fair comparison.
2Test A: 2.2k +rail15-A15; LED E15/F15; J15--railFirst brightness result.
3Test B: replace only the 2.2k with 2.7k in the same holesChanges one variable only.
4Test C: 2.2k +rail12-A12; 2.7k E12-A18; LED E18/F18; J18--railMakes one path through both resistors.
Only the resistor should change. If you move the LED or use a different battery, the comparison is not fair.
Check that electricity cannot bypass either resistor through a shortcut wire.

BUILD PATH

STEP 1 OF 7

Build the Mission 1 circuit using the 2.2k resistor

Try · Notice · ExplainRead the checkpoint, make a prediction, then test your idea.

Build the Mission 1 circuit using the 2.2k resistor.

See How Resistance Changes Light — Step 1

A video demonstration will appear here when it is ready. You can follow the written step now.

Read the video instructions

Build the Mission 1 circuit using the 2.2k resistor.

Need a diagram for this step?

WHAT'S REALLY HAPPENING?

Why it works

Resistance limits current. More resistance usually means less current and a dimmer LED. Engineers choose resistor values to protect parts and set signal levels.

Brightness controls, sensor circuits and electronic timing all depend on carefully selected resistance.

FAIR-TEST CHALLENGE

Change one feature, keep the rest the same and repeat your comparison.

WHEN IT DOESN'T WORK YET

Debug one clue at a time.

All tests look the same

Likely cause: Room light hides small differences

Try this first: Shade the LED from strong room light and compare again.

One setup does not light

Likely cause: Too much resistance or an open join

Try this first: Trace the resistor path and check every connection.

Ranking seems backwards

Likely cause: A resistor may be bypassed

Try this first: Remove extra wires and rebuild the shortest complete path.

CLEAN, RESET AND STORE

Switch off and disconnect all power. Let moving parts stop. Put the parts back in their kit compartments.

NEXT SKILL

Use two controls as an AND rule.