Basic Electrical and Electronics Engineering Practice Flashcards

A comprehensive set of vocabulary flashcards covering basic electrical circuits, AC/DC machines, electrical installations, and electronic devices such as diodes, BJTs, and FETs based on the course question bank.

Kirchhoff’s Voltage Law (KVL)

A foundational law for circuit analysis stating that the algebraic sum of the potential differences (voltages) around any closed loop or network is zero.

Kirchhoff’s Current Law (KCL)

A circuit law stating that the total current entering a junction or node is exactly equal to the total current leaving that node.

Mesh Analysis

A method used to simplify and solve complex DC circuits containing multiple loops by determining the mesh currents (e.g., $i_1$, $i_2$, $i_3$).

Nodal Analysis

A circuit analysis technique that uses Kirchhoff's Current Law (KCL) and nodal equations to determine the voltage at different nodes in a circuit.

RMS Value

The root mean square value of a sinusoidal waveform, which represents the effective value of an alternating current or voltage.

Power Factor (pf)

The ratio of real power (P) to apparent power (S) in an AC circuit, often influenced by lagging or leading currents.

Real Power (P)

The actual power consumed by a load in an AC circuit, measured in Watts ($W$) or kilowatts ($kW$).

Reactive Power (Q)

The power that oscillates between the source and the reactive components (inductors and capacitors), measured in Volt-Ampere Reactive ($VAR$).

Apparent Power (S)

The product of the RMS voltage and RMS current in an AC circuit, measured in Volt-Amperes ($VA$) or kilovolt-amperes ($kVA$).

Star (Y) Connection

A three-phase connection where one end of each of the three windings are connected together at a common neutral point; the line voltage ($V_L$) relates to phase voltage ($V_{ph}$) as $V_L = \sqrt{3}V_{ph}$.

Delta (\Delta) Connection

A three-phase connection where the three windings are connected in series to form a closed loop; the line current ($I_L$) relates to phase current ($I_{ph}$) as $I_L = \sqrt{3}I_{ph}$.

Switch Fuse Unit (SFU)

A protective device used in Low Voltage (LT) systems that combines the functions of a switch and a fuse for circuit protection.

Miniature Circuit Breaker (MCB)

An electromagnetic device that automatically breaks an electrical circuit during an overcurrent or short circuit to prevent damage.

Molded Case Circuit Breaker (MCCB)

A type of circuit breaker with a higher protection capacity than an MCB, commonly used in industrial installations for high current ratings.

Earth Leakage Circuit Breaker (ELCB)

A safety device used in electrical installations with high earth impedance to prevent shock by detecting small stray voltages on the metal enclosures of electrical equipment.

Ampere-hour (Ah) Rating

A rating that indicates the amount of charge a battery can deliver at a specific current for a specific amount of time.

Iron Losses

Also known as core losses, these occur in the transformer core due to hysteresis and eddy currents and remain constant regardless of the load.

Copper Losses

Variable losses in a transformer that occur in the primary and secondary windings due to the resistance of the wire, calculated as $I^2R$.

Back EMF

The electromotive force developed in a DC motor that opposes the applied voltage, acting as a regulating mechanism for the motor's speed and current.

Slip

The difference between the synchronous speed ($N_s$) and the actual rotor speed ($N$) of an induction motor, usually expressed as a percentage.

Cut-in Voltage

Also known as the threshold voltage, it is the minimum forward voltage required for a P-N junction diode to start conducting significantly (approx. $0.7\,V$ for Silicon).

Zener Diode

A special type of diode designed to operate reliably in the reverse-bias breakdown region, frequently used as a voltage regulator.

Ripple Factor

A measure of the effectiveness of a rectifier, defined as the ratio of the RMS value of the AC component in the output to the DC value of the output.

Bridge Rectifier

A type of full-wave rectifier that uses four diodes arranged in a bridge configuration to convert AC to DC without requiring a center-tapped transformer.

Common Emitter (CE) Configuration

A BJT configuration where the emitter is common to both the input and output circuits, typically providing high current and voltage gains.

Beta ($\beta$)

The current gain of a transistor in a Common Emitter configuration, defined as the ratio of collector current ($I_C$) to base current ($I_B$).

Pinch-off Voltage

The gate-to-source voltage ($V_{GS}$) at which the drain current ($I_D$) becomes zero because the depletion region has completely blocked the channel in a FET.