Definition
A material whose ability to conduct electricity falls between that of a conductor (like copper) and an insulator (like rubber). Its conductivity can be controlled by adding small amounts of other elements, by temperature, or by applied voltage, which is what makes it useful for building electronic components such as diodes and transistors.
Plain English
A material that conducts electricity only partly, and only when you want it to. By controlling it, you can use it as an electronic switch or valve for current.
Context Anchor
Seen in aircraft electrical and electronic system discussions, especially when studying solid-state devices, voltage regulators, sensors, and circuit components.
Derivation
From Latin semi- meaning 'half' and conductor from conducere, 'to lead together.' A semiconductor is literally a 'half-conductor' — it conducts, but only partway, which captures exactly how the material behaves.
Why Pilots Care
Nearly every modern avionics box, radio, and electronic control unit on the aircraft is built from semiconductors. Knowing what they are helps a technician understand why these components are sensitive to heat, static electricity, and voltage spikes.
Intuition Check
Do not read semiconductor as simply “half a conductor.” The important idea is control: it is a material whose ability to carry electricity can be changed and used in electronic circuits.
Example Sentence 1
The diode in the charging circuit is a semiconductor device that allows current to flow in one direction only.
Example Sentence 2
Modern avionics rely on semiconductors to process signals from the GPS and attitude sensors.