BUILD CARD · EASY

Pushbutton Blue LED

Press and hold a momentary switch to light a current-limited blue LED.

Learning goals

Build and check a 10×7 snap-grid circuit from a visual diagram.
A momentary button and correctly oriented blue LED turn a brief press into visible light.

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

Pressing the switch completes the current path.

The 100-ohm resistor limits current through the blue LED.

The LED positive terminal faces the battery positive side.

THE IDEAA momentary button and correctly oriented blue LED turn a brief press into visible light.

05 / TEST

What to do: Press and hold the button briefly, then release it.
What to expect: The blue LED lights only while the button completes the protected current path.

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 momentary button and correctly oriented blue LED turn a brief press into visible light.

What should I check first if it does not work?

Compare every part position and connection with the circuit diagram.