In a computer microchip, transistors act as switches, letting current through to represent the binary digit 1, or cutting it off to represent 0. Today many household appliances including televisions, VCRs, stereos, telephones, refrigerators, washers and dryers, microwave ovens, alarm systems, and fax machines have chips built into them. The chips allow the devices to process great volumes of information and provide the user with exactly the information desired, from identifying the name and phone number of a caller to playing and replaying the chorus of the latest hip-hop release. Transistors are also found in pacemakers, hearing aids, cameras, calculators, and watches. Most of these devices draw their power from tiny batteries.
Most spacecraft also rely on microchips, and thus transistors.
To introduce the importance of the invention of the transistor, help students visualize its impact on the design of computers. If possible, show students a vacuum tube. If a vacuum tube is not available, you might use a 25-watt light bulb as a model for the vacuum tube. The machine needed a lot of power to run and produced a tremendous amount of heat. Explain that they will be able to answer these and other questions in this project as they search for transistors all around them.