BUILD CARD · EASY
Two Lamps in Series
Place two identical lamps in one current path and compare their brightness with a parallel circuit.
- Time
- 15 min
- Age
- 8+
- Pieces
- 7
- Board
- 10×7
- Build and check a 10×7 snap-grid circuit from a visual diagram.
- Series lamps share one current path and divide the available supply voltage.
02 / PARTS CHECK
Parts list
- 1×8-snap wireconnector
- 1×3-snap wireconnector
- 1×2-snap wireconnector
- 2×2.5V lamplamp
- 1×Slide 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
Series components share one current path.
The battery voltage is divided across the two lamps, so each is dimmer than a single lamp.
If either lamp is removed, the only path is broken and both turn off.
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05 / TEST
Test and expected result
- What to do
- Close the switch, compare both lamps, then remove one lamp with power disconnected.
- What to expect
- Both lamps are dimmer than the parallel pair, and removing either lamp breaks the complete circuit.
06 / SAFETY
Build smart
- Use only two matching 2.5V lamps with the 3V holder.
- Do not short across a lamp or the battery.
- Open the switch after the observation.
07 / TROUBLESHOOTING
If it does not work
- Make sure both lamps are firmly snapped down.
- Check that no wire bypasses either lamp.
- Compare using the same batteries as the parallel circuit.
08 / FREQUENTLY ASKED QUESTIONS
Questions about this circuit
What is the main idea behind this circuit?
Series lamps share one current path and divide the available supply voltage.
What should I check first if it does not work?
Make sure both lamps are firmly snapped down.
09 / RELATED BUILDS
Try a similar circuit
Continue with another build that shares the same components, ideas, or difficulty.
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Connect two lamps across the same two supply rails and compare them with the series version.
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Hear the Motor
Recreate manual Project 30 by putting a motor and speaker in the same current path.