BUILD CARD · EASY

Magnetic Blinking LED

Bring a magnet near the reed switch to control a protected blinking LED.

Learning goals

Build and check a 10×7 snap-grid circuit from a visual diagram.
A magnetic reed contact can remotely power an LED with its own blinking circuit.

FINAL CIRCUITBOARD 10×7

02 / PARTS CHECK

Parts list

03 / ASSEMBLY

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

A nearby magnet closes the reed switch without direct contact.

The blinking LED contains its own flashing control circuit.

The series resistor limits current while the LED flashes.

THE IDEAA magnetic reed contact can remotely power an LED with its own blinking circuit.

05 / TEST

What to do: Move a magnet toward the reed switch, hold it nearby, then move it away.
What to expect: The blinking LED runs while the magnetic field keeps the reed contacts closed.

06 / SAFETY

Use only the recommended battery pack and voltage.
Disconnect the battery before moving or replacing parts.
Stop immediately if a part becomes hot, smells unusual, or behaves unexpectedly.

07 / TROUBLESHOOTING

Compare every part position and connection with the circuit diagram.
Check that every snap connection is firm and the batteries still have power.
Confirm polarized parts such as LEDs, diodes, and transistors face the correct direction.

08 / FREQUENTLY ASKED QUESTIONS

What is the main idea behind this circuit?

A magnetic reed contact can remotely power an LED with its own blinking circuit.

What should I check first if it does not work?

Compare every part position and connection with the circuit diagram.