BUILD CARD · EASY
Press Switch LED
Make a white LED light only while you hold down the press switch.
- Time
- 12 min
- Age
- 8+
- Pieces
- 6
- Board
- 10×7
- Build and check a 10×7 snap-grid circuit from a visual diagram.
- A momentary switch completes the LED circuit only while you hold it down.
02 / PARTS CHECK
Parts list
- 1×7-snap wireconnector
- 1×3-snap wireconnector
- 1×White LEDsemiconductor
- 1×100 Ω resistorresistor
- 1×Press 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 press switch closes the circuit only while it is held down.
The resistor limits current to protect the LED.
The LED must face the correct direction.
Explore more led circuit projects →
05 / TEST
Test and expected result
- What to do
- Press and hold the momentary switch, then release it.
- What to expect
- The LED lights only while the switch is held because the contacts reopen when released.
06 / SAFETY
Build smart
- Use only the 3V battery holder.
- Never bypass the resistor or short the battery.
- Disconnect the battery after use.
07 / TROUBLESHOOTING
If it does not work
- Keep the press switch held down while testing.
- Reverse the LED if it does not light.
- Check every snap and battery direction.
08 / FREQUENTLY ASKED QUESTIONS
Questions about this circuit
What is the main idea behind this circuit?
A momentary switch completes the LED circuit only while you hold it down.
What should I check first if it does not work?
Keep the press switch held down while testing.
09 / RELATED BUILDS
Try a similar circuit
Continue with another build that shares the same components, ideas, or difficulty.
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Replace the color LED in manual Project 2 with a blue LED and keep the current-limiting resistor.
Magnetic Color Light
Bring a magnet near the reed switch to power the color LED safely.
Morse Code LED
A safe LED variation of manual Project 103 for practicing short and long light pulses.