BUILD CARD · EASY
Magnetic Color Light
Bring a magnet near the reed switch to power the color LED safely.
- Time
- 15 min
- Age
- 8+
- Pieces
- 6
- Board
- 10×7
- Build and check a 10×7 snap-grid circuit from a visual diagram.
- A magnet closes the reed switch and powers the protected color LED.
02 / PARTS CHECK
Parts list
- 1×7-snap wireconnector
- 1×3-snap wireconnector
- 1×Color LEDsemiconductor
- 1×100 Ω resistorresistor
- 1×Reed switchswitch
- 1×3V two-cell battery holderpower
03 / ASSEMBLY
How to build the circuit
- 1
Disconnect the battery and clear the base grid before placing any part.
- 2
Match the final diagram one grid position at a time, placing connecting wires and lower layers first.
- 3
Check the direction of every LED, diode, transistor, battery, and other terminal-sensitive part.
- 4
Press every shared snap firmly, check that no wire shorts the battery, then connect power last.
04 / FIELD NOTES
How it works
The magnet closes the reed contacts without touching them.
The resistor protects the color LED.
Removing the magnet turns the light off.
Explore more led circuit projects →
05 / TEST
Test and expected result
- What to do
- Bring a magnet close to the reed switch, then remove it.
- What to expect
- The color LED runs only while the magnetic field closes the contacts.
06 / SAFETY
Build smart
- Use only the 3V two-cell battery holder.
- Never connect the battery terminals directly together.
- Disconnect the battery before moving any component.
07 / TROUBLESHOOTING
If it does not work
- Press every overlapping snap down firmly.
- Check the battery direction and replace weak batteries.
- Compare every component position with the final diagram.
08 / FREQUENTLY ASKED QUESTIONS
Questions about this circuit
What is the main idea behind this circuit?
A magnet closes the reed switch and powers the protected color LED.
What should I check first if it does not work?
Press every overlapping snap down firmly.
09 / RELATED BUILDS
Try a similar circuit
Continue with another build that shares the same components, ideas, or difficulty.
Blue LED Switch Light
Replace the color LED in manual Project 2 with a blue LED and keep the current-limiting resistor.
Pushbutton Color Light
A momentary-switch version of manual Project 2 with a protected color LED.
Tap-Triggered Blinking LED
Tap the board to energize a blinking LED through a vibration switch.