Metal Foil Tape Parallel-Plate Capacitor

A capacitor is a circuit element that can store charge, which can later be released as electrical energy. These instructions will show you how to make a very simple capacitor that may not be particularly useful if you are trying to build an electronic circuit, but is helpful in understanding how capacitors work.

You will need:

• Metal foil tape (example)
• Scissors
• Plastic box lid
• Wires with alligator clips (not required but useful for connecting and measuring)
• Meter that measures capacitance (if you want to know the value of your capacitor)

Cut two pieces of foil tape of equal size. Cut a rectangle out of the corner of each piece so that a small tab sticks out. Fold half of this tab over on itself. This will create a terminal you can easily clip wires to.

A dielectric is simply any non-conducting material that is layered between the capacitor plates. Air or vacuum can be a dielectric, but solid materials produce more capacitance and are easier to stick foil tape to. Stick your pieces of foil tape on either side of the plastic container lid, lining them up with each other.

Clip wires from each tab to one of the probes of a meter that measures capacitance and use it to determine the value of your capacitor.

You can experiment further to understand how capacitors work. What if you use several pieces of tape to make larger plates? What if you add layers of tape on top of each other? Try making two or more capacitors and wiring them in series or parallel. Capacitors in parallel will have an increased capacitance, and capacitors wired in series will have decreased capacitance.