What Are Electric Charge and Electrons?
Electric charge is a fundamental property of matter that can be positive or negative; its unit is the coulomb (C). The electron is a negatively charged subatomic particle that moves through conductors to create current. One electron's charge is about 1.6 × 10⁻¹⁹ C. Opposite charges attract, like charges repel.
Electric charge is a fundamental property of matter, and it comes in two types: negative (the electron) and positive (the proton). In electronics, the particle that actually carries the current is the electron, which orbits the atom and can move around easily.
The Unit of Charge: the Coulomb (C)
The unit of electric charge is the coulomb (C). 1 coulomb equals the total charge of about 6.24 × 10¹⁸ electrons. The relationship between current and charge is clear: 1 ampere = 1 coulomb of charge passing per second.
Like Charges Repel, Opposite Charges Attract
Two negative (or two positive) charges repel each other; a negative and a positive charge attract. This attraction-repulsion force is at the base of electron movement in circuits.
Conductor, Insulator and Semiconductor
How easily a material passes electricity depends on how many free electrons it has:
| Type | Behavior | Example |
|---|---|---|
| Conductor | Passes electricity easily | Copper, gold, aluminum |
| Insulator | Doesn't pass it (insulates) | Plastic, glass, rubber |
| Semiconductor | Passes it depending on conditions | Silicon, germanium |
Why Are Semiconductors Important?
Because semiconductors can behave like a conductor or an insulator depending on conditions, they form the basis of all modern electronics — diodes, transistors and microchips.
Common Mistakes
- Confusing charge with current: charge (coulombs) is an amount; current (amperes) is the flow rate of charge.
- Thinking "electrons go from + to −": electrons flow from − to +; the + to − direction is the conventional current direction.
Frequently Asked Questions
What is the unit of electric charge?+
What carries current?+
How do charges interact?+
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