Single-Phase Circuits Lecture Notes

A comprehensive set of vocabulary flashcards derived from the lecture notes on Single-Phase Circuits for exam preparation.

Single-Phase Circuit

An electrical circuit that uses a single AC voltage waveform.

Impedance (Z)

A complex quantity representing the total opposition to current flow in an AC circuit, composed of resistance (R) and reactance (X).

Ohm's Law

A fundamental law stating that the current (I) through a conductor between two points is directly proportional to the voltage (V) across the two points, represented by V = I Z.

Power Factor (pf)

The ratio of real power (P) to apparent power (S) in an AC circuit, indicating the efficiency of power usage.

Passive Sign Convention

A convention where current entering the positive terminal of an element is considered positive, leading to a correct sign for power calculation.

Phasor

A complex number representation of a sinusoidal function, illustrating the magnitude and phase angle of the waveform.

Root Mean Square (Vrms)

A value representing the effective voltage or current in an AC circuit, calculated as the square root of the average of the squares of instantaneous values.

Instantaneous Power (p(t))

The power at a specific moment in time, calculated as the product of instantaneous voltage and current.

Average Power (P)

The average value of power consumed over a complete cycle, calculated by integrating the instantaneous power over time.

Complex Power (S)

A power quantity in AC circuits that combines real power (P) and reactive power (Q), expressed in volt-amperes (VA).

Real Power (P)

The actual power used by a load, measured in watts (W), defined as P = VIcos(θ).

Reactive Power (Q)

The power that alternates between the source and reactive components in an AC circuit, measured in volt-amperes reactive (VAR).

Load Voltage Regulation

A measure of how much the voltage drops under load compared to the no-load voltage, expressed as a percentage.

Kirchhoff’s Current Law (KCL)

A principle stating that the sum of currents entering a node is equal to the sum of currents exiting the node.

Circuit Analysis Techniques

Methods such as mesh and nodal analysis used to analyze electrical circuits using Kirchhoff’s laws.

Thévenin's Theorem

A method that simplifies a linear circuit to a voltage source (Voc) in series with an impedance (ZTh) at the terminals of the load.

Nodal Analysis

A circuit analysis method providing a systematic approach to solving for node voltages using KCL.

Leading and Lagging Current

Describes the phase relationship between current and voltage in a circuit; current 'leads' voltage in capacitive circuits and 'lags' in inductive circuits.

Current Divider Rule

A formula to find the current flowing through a particular branch in a parallel circuit based on its impedance.

Voltage Divider Rule

A formula to find the voltage drop across a component in a series circuit based on its resistance.

Power Factor Correction

The procedure of improving lower power factor loads by adding capacitors to reduce reactive power requirements.

AC Circuit Components

Elements of an AC circuit, typically includes voltage source, resistance, inductance, and capacitance.

Impedance Triangle

Graphical representation of the relationship between resistance (R), reactance (X), and impedance (Z) in a circuit.