Glossary
Breakdown Voltage
The minimum voltage at which an insulator or dielectric material loses its insulating properties and becomes electrically conductive, often leading to material damage or failure.
Example:
If a capacitor is subjected to a voltage exceeding its breakdown voltage, the dielectric material can be permanently damaged, causing a short circuit.
Capacitance
A capacitor's ability to store electric charge for a given voltage. It is a fundamental property of a capacitor, measured in Farads (F).
Example:
A camera flash unit relies on a capacitor with high capacitance to quickly discharge a large amount of energy for illumination.
Capacitor
An electronic component designed to store electrical energy in an electric field between two conductive plates separated by an insulating material (dielectric).
Example:
A capacitor in a car audio system can store energy to provide a quick burst of power to the amplifier for deep bass notes.
Conduction Band
An energy band in a material where electrons are free to move and conduct electricity. In conductors, this band overlaps with the valence band, allowing for easy electron flow.
Example:
In metals, electrons readily occupy the conduction band, which explains their excellent electrical conductivity.
Conductivity
A measure of how well a material conducts electricity. It is the inverse of resistivity, indicating the ease with which electric current flows through a substance.
Example:
Copper's high conductivity makes it an excellent choice for electrical wiring.
Conductor
A material that allows electric charge to flow easily through it due to the presence of free electrons. Metals are common examples.
Example:
Aluminum is a lightweight conductor often used in overhead power lines.
Coulomb's Law
A fundamental law in electrostatics that quantifies the force between two stationary, electrically charged particles. The force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
Example:
Using Coulomb's Law, physicists can calculate the attractive force between an electron and a proton in a hydrogen atom.
Dielectric
An electrically insulating material placed between the plates of a capacitor to increase its capacitance and prevent short circuits. It enhances the capacitor's ability to store charge.
Example:
Paper is often used as a dielectric in some types of capacitors due to its insulating properties and ability to increase capacitance.
Dielectric Constant (κ)
A dimensionless factor that describes how much a dielectric material increases the capacitance of a capacitor compared to a vacuum. A higher value indicates greater charge storage capability.
Example:
Inserting a material with a high dielectric constant between capacitor plates allows for more charge storage at the same voltage.
Electric Field
A region around a charged particle or object within which a force would be exerted on other charged particles. It is a vector quantity that describes the influence of charge.
Example:
The electric field between the plates of a charged capacitor stores the electrical potential energy.
Energy Stored in a Capacitor
The potential energy stored in the electric field between the plates of a charged capacitor. This energy can be calculated using formulas like U = ½CV².
Example:
A defibrillator uses the energy stored in a capacitor to deliver a powerful electrical shock to restart a heart.
Insulator
A material that significantly resists the flow of electric current. Its electrons are tightly bound and do not move freely.
Example:
The rubber coating on electrical tools acts as an insulator to protect users from electric shock.
Polarization
The process by which the positive and negative charges within a dielectric material separate slightly when subjected to an external electric field, creating induced electric dipoles.
Example:
When a dielectric is placed in an electric field, its molecules undergo polarization, which reduces the net electric field within the material.
Resistance
A measure of the opposition to the flow of electric current within a circuit or material. It is measured in Ohms (Ω).
Example:
A heating element in a toaster works by having high resistance, which converts electrical energy into heat.