FUN DAMENTALS FOR THE BEGINNER
A kit for these experiments can be purchased from
the Nuts & Volts Webstore at
www.nutsvolts.com or call us at 800-783-4624.
HOW A CAPACITOR WORKS
The function of a capacitor is to store an electrical charge. In this
circuit, we will watch an LED slowly dim as the capacitor
1. Build the Circuit.
Using the schematic along with the pictorial diagram, place
the components on a solderless breadboard as shown. Verify
that your wiring is correct.
2. Do the Experiment.
Theory: Electronics flow from the battery through the LED,
through the resistors, and back to the battery. Electrons also flow
from the battery to charge up the capacitor. When we remove
the battery from the circuit, electrons in the charged capacitor
will flow through the LED and keep it lit until the capacitor
Procedure: Connect a nine-volt battery to the battery snap
and observe that the LED is lit. Next, remove one lead of the
battery snap from the circuit board and observe that the LED
remains lit for a moment. Now, change the capacitor to the 100
µF, then connect and disconnect the battery. Do this again with
the 1,000 µF and observe the LED.
As you should have seen, the LED remains lit temporarily
after the battery is disconnected from the circuit because the
electrical energy stored in the capacitor flows from the negative
side of the capacitor through the LED and the 330 ohm resistor
to the positive side of the capacitor. The LED should have
remained lit longer with the 1,000 µF capacitor than it did with
the 100 µF.