Mini solar panel circuit
A small solar panel lights an LED or spins a toy motor. Test it in sun, in shade and at different angles.
The big idea
A solar panel turns light straight into electricity. The more light that hits it, the more electricity it makes. This experiment lets students see that for themselves, with a panel they can hold.
You will need
Tick things off as you gather them.
Step by step
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Step 1: Find plus and minus
Look at the panel wires. Red is plus and black is minus. If there are no colours, the panel back usually has + and − printed on it.
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Step 2: Wire the LED
Join the panel plus wire to the resistor. Join the resistor to the long leg of the LED. Join the short leg of the LED back to the panel minus wire.
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Step 3: Test in full sun
Take the panel outside and point it straight at the Sun. The LED should glow. If it does not, swap the LED legs round.
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Step 4: Move it to shade
Carry the panel into shade, then indoors. Watch how the LED dims. Write down what you see in each place.
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Step 5: Try different angles
Hold the panel flat, then tilted at about 30, 60 and 90 degrees to the Sun. Use the angle card. Note the brightness each time, or the voltage if you have a multimeter.
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Step 6: Swap in the motor
Disconnect the LED and connect the toy motor instead. Does it spin faster in stronger light? Cover half the panel with paper and see what changes.
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Step 7: Make a results table
Draw a table with the columns place, angle and result. Fill it in. Which condition gave the most power?
What to look for
- The LED is brightest when the panel faces the Sun directly.
- In shade the LED is dim, and indoors it may not light at all.
- Covering half the panel cuts the power, not just the brightness.
An example of the pattern you should see, not measured data. Your numbers will differ, and that is fine.
Why it works
A solar cell is made of thin layers of silicon. When light hits it, the light knocks tiny charged particles called electrons loose. The cell is built so that these electrons flow one way round your circuit. More light frees more electrons, so you get more current. A panel pointing straight at the Sun catches the most light, which is why real solar farms tilt their panels.
Try this next
- Add a second panel in series (plus to minus) and see what happens to the voltage.
- Find the best angle for your school at noon.
- Try coloured plastic over the panel and see which colour lets the most light through.
Stay safe
Panels this small are safe to handle. Never look at the Sun directly.
Link to the grid
A rooftop solar plant is this circuit made large. Many panels are wired together and their direct current is turned into the alternating current the grid uses.
Learn how the grid worksMore sun power experiments
Solar cooker
A cardboard box, foil and plastic wrap trap the Sun's heat. Melt chocolate, warm water or cook rice.
Solar water heater
Black-painted bottles or pipe in the Sun heat water. Measure the temperature as it rises.
Shadow-tracking solar map
Track shadows on the school roof through the day to find the best place for solar panels.