Home >> Science & Nature >> Science

How to Book Homemade Capacitors

Early wireless sets relied on bulky variable capacitors to adjust the tuning circuits, enabling listeners to choose between radio stations broadcasting on different frequencies. A capacitor, essentially two or more metal plates separated by an insulator, or dielectric, serves many electrical purposes, including energy storage, signal filtering and direct current smoothing. Electrical labs in many schools include experiments with homemade components, and building a simple ̶0;book capacitor̶1; using inexpensive, easily obtained materials is a task that students can attempt at home.

Things You'll Need

Large book
Aluminum foil
Stranded connecting wire
Cellulose tape

Instructions

- 1
  Choose a large book, ideally one with pages made from thin paper. Open the book about halfway through and place it on a flat surface.
- 2
  Cut two sheets of aluminum foil, each just smaller than a single page of the book. Cut two 6-inch lengths of connecting wire and remove a half-inch of insulation from each end of the wires.
- 3
  Attach the connecting wires to the foil sheets. Place the end of one wire on a corner of one of the sheets, making sure that the strands are directly in contact with the foil. Tape the strands in place, taking care not to crumple the foil. Repeat for the second sheet.
- 4
  Place one sheet of foil on one page of the open book, making sure that the wire sticks out from the pages. Turn the adjacent page so that it covers the foil.
- 5
  Place the second sheet of foil on top of the page that you just turned, with the connecting wire at the opposite end from the one attached to the first sheet. Close the book carefully so that the foil sheets are sandwiched between the pages, forming a capacitor. Make sure that the sheets remain inside the book and do not touch each other.
- 6
  Connect the capacitor to a test circuit with the wires if you wish. Change its capacitance by pressing the pages of the book together more or less tightly.

Science