Concept To Remember

Electrical Energy And Power

1. Power:

Power is the rate at which electrical energy is consumed or generated.
The SI unit of power is Watts (W).
$$P = VI$$ [Formula]
Factors affecting power are: voltage, current, and resistance.
Power rating refers to the maximum amount of power an electrical device can safely handle.

2. Energy:

Electric energy is the capacity of an electric current to do work.
The SI unit of energy is Joules (J) or kilowatt-hours (kWh).
$$E = Pt$$ [Formula]
Factors affecting energy are: power, time, and voltage.
Energy consumption refers to the amount of electrical energy used by a device or system.

3. Current and Voltage:

Electric current (I) refers to the flow of electric charge (electrons) through a conductor. The standard unit for measuring current is the ampere (A).
Voltage (V) refers to the electrical potential difference between two points in a circuit or the energy per unit charge that results in motion through the said circuit; its unit of measurement is the volt (V).
Ohm’s Law: V = I × R where R = resistance

4. Circuits:

Electrical circuits consist of conductive pathways allowing currents to flow, typically containing sources of electric potential, loads like light bulbs, resistors, switches, transformers, etc.
There are two primary types of circuit configurations: • Series circuit: Elements are connected end-to-end where charges follow one specific path; the total current for an entire series is equivalent to that passing through any component of the same series
• Parallel circuit: Elements are connected side-by-side, providing several alternate routes for current flow.
Series, Parallel combinations [Variations/Special cases]

5. AC Circuits:
-Alternating current involves periodically reversing current direction and continuously shifting through a sine wave pattern.

Alternating current (AC) circuits feature continually changing directions in power flow and involve parameters like frequency, phase angle, reactance, and impedance in their analyses.

Frequency determines how rapidly AC waveforms complete cycle reversals measured in Hertz (Hz).
Voltage and current can be “out of sync” with phase angles as an additional circuit trait to comprehend [Phase shifts]