Electronics & Control Systems – Key Vocabulary

Comprehensive vocabulary list covering AC theory, filters, ICs, rectifiers, regulators, ESD, transducers, phase control, control systems, and measuring instruments for exam practice.

Alternating Current (AC) Theory

Branch of electrical theory dealing with time-varying sinusoidal voltages and currents.

Selectivity

A receiver’s ability to discriminate between signals of different frequencies.

Low-Pass Filter

Circuit that passes low-frequency signals while attenuating high-frequency components.

High-Pass Filter

Circuit that passes high-frequency signals while attenuating low-frequency components.

Time Constant (τ)

Time for current or voltage in an RC/RL circuit to reach 63.2 % of its final value.

Harmonic

Signal component whose frequency is an integer multiple of the fundamental frequency.

Bandwidth

Continuous range of frequencies selected or passed by a system.

Q Factor (Quality Factor)

Ratio of reactive impedance to resistance in a resonant circuit; indicates selectivity.

RC Differentiator

RC network with short τ acting as a high-pass filter that produces spike-like outputs.

RL Differentiator

RL network with short τ; high-pass behaviour, output taken across inductor.

RC Integrator

RC network with long τ acting as a low-pass filter; output taken across capacitor.

RL Integrator

RL network with long τ acting as a low-pass filter; output taken across resistor.

Coupling Capacitor

Capacitor that blocks DC while allowing AC to pass between circuit stages.

Triangular Wave

Periodic waveform with linear rise and fall; contains only odd harmonics.

Square Wave

Waveform alternating between two levels with 50 % duty; comprises fundamental plus infinite odd harmonics.

Saw-Tooth Wave

Waveform with linear rise and abrupt fall; contains both odd and even harmonics.

Symmetrical Waveform

Wave whose positive and negative halves are identical in magnitude and duration.

Asymmetrical Waveform

Wave whose positive and negative halves differ; e.g., saw-tooth.

Integrated Circuit (IC)

Micro-electronic device containing interconnected transistors, resistors, etc., on a single chip.

Dual In-Line Package (DIP)

IC package with two parallel rows of through-hole pins.

Surface-Mount Technology (SMT) Package

IC package designed for direct mounting on PCB surface; high density.

Pin Grid Array (PGA)

Package with an array of pins on the underside, used for microprocessors.

Ball Grid Array (BGA)

Package that uses solder balls on underside for high-density interconnection.

Chip Carrier (CC)

Rectangular IC package with contacts on all four sides.

Bridge Rectifier

Diode network converting AC to full-wave DC.

Integrated Bridge Rectifier

Monolithic bridge rectifier packaged as a single component.

Single-Phase Bridge Rectifier

Four-diode bridge for rectifying single-phase AC.

Three-Phase Bridge Rectifier

Six-diode bridge used with three-phase AC supplies.

Centre-Tap Bridge Rectifier

Rectifier using a centre-tapped transformer winding plus diodes to produce DC.

Half-Wave Rectifier

Circuit using one diode to pass only one half-cycle of AC.

Full-Wave Rectifier

Circuit converting both halves of AC waveform to DC using four diodes or centre tap.

Voltage Regulator

Device or circuit maintaining constant output voltage despite load or input changes.

Fixed Positive Voltage Regulator

Regulator delivering a set positive output voltage (e.g., 7805 → 5 V).

Fixed Negative Voltage Regulator

Regulator providing a set negative voltage (e.g., 7905 → –5 V).

Adjustable Voltage Regulator

Regulator whose output voltage can be set within specified limits (e.g., LM317).

Dual-Tracking Voltage Regulator

Regulator that provides matched positive and negative outputs.

Series Voltage Regulator

Linear regulator with control element in series with load.

Shunt Voltage Regulator

Regulator that diverts excess current to ground; less efficient.

Linear Regulator

Regulator using linear control element; simple, low noise, but inefficient.

Switching Regulator

Regulator using high-frequency switching for high efficiency.

Boost Converter (Step-Up)

Switching regulator that raises output voltage above input.

Buck Converter (Step-Down)

Switching regulator that lowers output voltage below input.

Inverter Regulator

Switching converter that produces AC or reversed polarity from DC input.

Electrostatic Discharge (ESD)

Sudden flow of static electricity between objects of different potentials.

Electrostatic Discharge Sensitivity (EDS)

Degree to which a component is vulnerable to ESD damage.

Human Body Model (HBM)

ESD test model simulating discharge from a charged person.

Machine Model (MM)

ESD stress model representing discharge from machinery.

Charged Device Model (CDM)

ESD model where the device itself becomes charged and discharges.

Complementary MOS (CMOS)

Logic family using complementary n- and p-channel MOSFETs; low power.

MOSFET

Metal-Oxide-Semiconductor Field-Effect Transistor; voltage-controlled device.

Transducer

Device converting one form of energy into another measurable signal.

Active Transducer

Transducer that generates its own electrical output without external power.

Passive Transducer

Transducer requiring external power and producing modulated output.

Potentiometer

Variable resistor used for voltage division or displacement measurement.

Potentiometer Resolution

Smallest change in resistance ratio a potentiometer can detect.

Strain Gauge

Sensor measuring strain via resistance change in a conductor.

Thermistor

Temperature-sensitive resistor with either negative (NTC) or positive (PTC) coefficient.

NTC Thermistor

Thermistor whose resistance decreases as temperature rises.

PTC Thermistor

Thermistor whose resistance increases with temperature.

Wheatstone Bridge

Circuit for precise resistance or sensor measurement using a four-resistor network.

Light Dependent Resistor (LDR)

Resistor whose resistance decreases with increasing light intensity.

Photodiode

Semiconductor diode that generates current when exposed to light.

Phototransistor

Transistor that responds to light, offering current amplification.

Linear Variable Differential Transformer (LVDT)

Inductive transducer converting linear displacement to AC voltage.

Current Transducer

Sensor providing electrical output proportional to current flow.

Voltage Transducer

Device converting AC input voltage to proportional DC output signal.

Infrared (IR) Detector

Sensor detecting infrared radiation, often using photodiodes or phototransistors.

Tacho-Generator

Generator producing voltage proportional to rotational speed for feedback control.

Thyristor

Family of four-layer semiconductor switches including SCRs and TRIACs.

Silicon Controlled Rectifier (SCR)

Unidirectional thyristor conducting when gate-triggered.

Trigger Angle

Portion of AC cycle during which a thyristor remains non-conductive before firing.

Conduction Angle

Portion of AC cycle during which a thyristor conducts.

Light-Activated SCR (LASCR)

SCR that can be triggered by incident light.

TRIAC

Bidirectional thyristor controlling AC in both polarities.

Diac

Bidirectional trigger diode used to fire TRIACs.

Quadrac

Device combining a TRIAC and Diac in one package for phase control.

Phase Control

Method of regulating AC power by adjusting the firing angle of thyristors.

Open-Loop System

Control system without feedback; output not compared to input reference.

Closed-Loop System

Control system using feedback to reduce error and maintain desired output.

Setpoint

Desired target value for a controlled variable in a feedback system.

Error Signal

Difference between setpoint and actual output in closed-loop control.

Controller

Device/algorithm adjusting input to a process based on error signal.

Analogue Signal

Continuous-time electrical signal representing a physical variable.

Digital Signal

Signal defined by discrete voltage levels, typically logic 0 and 1.

Pulse Amplitude Modulation (PAM)

Modulation scheme where pulse height represents sample amplitude of analogue signal.

Analogue-to-Digital Converter (ADC)

Circuit converting analogue input into digital output code.

Ramp ADC

ADC comparing input to a linearly increasing reference ramp.

Integrating ADC

ADC that integrates input voltage over time before comparison.

Dual-Slope ADC

ADC that integrates input then a reference of opposite polarity for accurate conversion.

Successive Approximation ADC

ADC using binary search to converge on input voltage value.

Flash ADC

High-speed ADC using parallel comparators and priority encoder.

Sample-and-Hold Circuit

Circuit that captures and stores an analogue value for conversion.

Binary Counter

Sequential logic circuit that counts clock pulses in binary form.

Schmitt Trigger

Comparator circuit with hysteresis for clean switching of noisy signals.

Input Attenuator

Resistive divider used to scale down large input signals for measurement.

Digital Voltmeter (DVM)

Instrument converting and displaying analogue voltage as digital value.

Frequency Counter

Instrument that measures signal frequency by counting cycles over a precise time base.

Voltage-to-Frequency Converter

Circuit producing output frequency proportional to input voltage.

Staircase Voltmeter

Voltmeter using incremental reference steps and comparator to determine unknown voltage.

Successive Approximation Register (SAR)

Logic register in SAR-ADC that stores and updates trial codes during conversion.