Electricity Fundamentals

Study Notes

Electricity is a controllable and versatile form of energy used in various domains such as homes, schools, hospitals, and industries.

Electric current represents the movement of electric charges through conductors like metallic wires.
Electric current is measured in amperes (A) and denotes the rate of flow of electric charges.
The unit of electric charge is the coulomb, with one coulomb equivalent to approximately 6 × 10^18 electrons.
An ammeter, connected in series in a circuit, measures electric current, displaying the flow from the positive to the negative terminal of a cell through components like bulbs.

Electrons, negatively charged particles, are the actual carriers of current.
In metals, electrons move with an average speed despite encountering resistance from atoms within the solid conductor.
Despite relatively slow motion, the current itself flows nearly at the speed of light, allowing devices such as bulbs to instantaneously illuminate upon activation.

Electric potential difference, analogous to pressure difference in fluid flow, drives the movement of charges within a conductor.
The unit of potential difference is the volt (V), named after Alessandro Volta.
A voltmeter, connected in parallel to the components being measured, quantifies the potential difference between two points in a circuit.

Circuit diagrams, represented with symbols, elucidate the components of an electric circuit, simplifying comprehension and analysis.
Ohm's Law elucidates the relationship between potential difference across a conductor and the current through it, establishing a direct proportionality between the two.

Resistance, a constant characteristic of a given conductor, quantifies its opposition to current flow.
Factors influencing resistance include length, cross-sectional area, and material composition.
Resistors can be connected in series or parallel, with each configuration impacting the total resistance and current flow differently.

The heating effect of electric current arises as current flows through a conductor, generating heat due to resistance.
This phenomenon finds practical applications in devices like electric heaters and toasters, where electrical energy is converted into heat for various purposes.