Glossary
conductor
A conductor is a material that lets electric charge flow through it freely. Copper and aluminum do it best, which is why wires and cables are made of copper.
A conductor is a material that lets electric charge flow through it freely. Copper and aluminum conduct best, which is why wires are made of copper, and most metals plus salt water conduct as well.
Metals conduct because some of their electrons are free to move through the material. Materials sort into three classes: conductors at one end, insulators at the other, and semiconductors in between, which allow charge through only under the right conditions. That middle class is what electronics is built on.
Two contrasts are worth keeping straight. A conductor lets current through while a resistor deliberately limits it. A conductor carries the current while an insulator blocks it, and in any cable one wraps the other so the current reaches the device and not your hand. Water is worth remembering as a hazard, since a person standing in it becomes part of the conducting path.
Taught in
Related terms
- insulator — An insulator is a material that does not let charge flow — rubber, glass, plastic, dry wood. It is why a wire is wrapped and a tool handle is covered.
- GFCI — A GFCI is a ground fault circuit interrupter: an outlet or breaker that compares the current going out with the current coming back, and cuts the power the instant the two differ.
Source: Official ASVAB — subtest descriptions (what each subtest asks) and the CAT-ASVAB scored-question counts (accessed 2026-09)