STEM/Robotics/ATL Tinkering Curriculum | Level 1 | Experiment 4 | Capacitor as charge Storing Device
To demonstrate how a capacitor stores charge and powers an LED after the power source is removed.
Materials Required:
Capacitor (100 µF or larger)
Resistor (1 kΩ)
Breadboard
DC Power Supply (5V or 9V battery)
LED (Light Emitting Diode)
Connecting wires
Theory:
Capacitors store energy in the form of an electric field. When a capacitor is connected to a power supply, it charges up to the supply voltage. After the power supply is removed, the stored charge can continue to power components like an LED until the capacitor discharges. The duration of this discharge depends on the capacitance and the resistance in the circuit.
Circuit Diagram:
Connect the positive terminal of the battery to one leg of the resistor (1 kΩ).
Connect the other leg of the resistor to the positive terminal of the capacitor.
Connect the negative terminal of the capacitor to the negative terminal of the battery (ground).
Connect an LED in parallel with the capacitor: the anode (longer leg) of the LED connects to the positive terminal of the capacitor, and the cathode (shorter leg) to the negative terminal of the capacitor.
Procedure:
Assemble the circuit as per the diagram.
Turn on the power supply (connect the battery).
The capacitor will begin charging, and the LED will light up immediately.
Allow the capacitor to fully charge (wait a few seconds, depending on the capacitance value).
Once the capacitor is charged, disconnect the battery by removing the wire from the positive terminal of the battery.
Observe the LED: it will remain lit for a period of time, gradually dimming as the capacitor discharges.
Observation:
Initially, the LED is bright because the capacitor is fully charged.
As the capacitor discharges, the brightness of the LED gradually decreases until it eventually turns off when the capacitor is fully discharged.
Conclusion:
The capacitor stores charge when connected to a power source and can release that stored charge to power components like an LED after the power source is removed. This demonstrates the function of a capacitor as a temporary energy storage device.