Semiconductor Devices

Definition

Electronic components made from semiconductor materials such as silicon, whose conductivity can be controlled to switch, amplify, or convert electrical signals.

Key points

• A diode allows current to flow in only one direction; it is used as a rectifier to convert alternating current into direct current.
• A transistor can act as a switch or an amplifier and is the building block of integrated circuits and microprocessors; the invention of the transistor (1947, Bell Labs) launched modern electronics.
• A light emitting diode (LED) converts electricity directly into light with high efficiency and is now standard in lighting and displays.
• Doping is the deliberate addition of impurities to a pure semiconductor to make n-type (extra electrons) or p-type (extra holes) material; a p-n junction is the basis of diodes, transistors, and solar cells.
• Solar cells (photovoltaic cells) are semiconductor devices that convert sunlight directly into electricity.

Why it matters for CAPF

The diode as a rectifier, the transistor as switch and amplifier, the LED, doping into n-type and p-type, and the solar cell are core electronics facts within the everyday science syllabus.

Common confusion

A diode conducts in only one direction, so it rectifies but does not amplify; amplification is the transistor's role. Doping does not make a semiconductor a conductor in the metallic sense; it controls a still-limited conductivity, which is exactly what makes switching possible.

Related concepts

concept semiconductors, concept superconductors, concept types of renewable energy

Parent note

physics everyday