Year 11 Systems Engineering: Electrical Fundamentals & Components

Comprehensive vocabulary flashcards covering Year 11 Systems Engineering topics including electrical units, circuit principles, safety, voltage regulation, passive components, semiconductors, motors, and electromechanical actuators.

Conductor

A material that allows electricity to easily flow through it, preserving voltage along its length.

Insulator

A material that resists electrical current flow, causing voltage to degrade rapidly along its length.

Semiconductor

A material whose conductivity lies between a conductor and an insulator (most commonly silicon), conducting under specific conditions.

Conventional Current

The standard convention that electric current flows from the positive terminal ($+\text{ charge}$) to the negative terminal, opposite to the flow of electrons.

Breadboard

A reusable prototyping base with sprung holes connected in rows and power rails, allowing quick insertion and modification of components before soldering to a PCB.

Veroboard

A through-hole prototyping board featuring a grid of pre-drilled holes connected in parallel strips of copper tracks.

Surface Mount Technology (SMT)

A PCB fabrication method where electronic components are soldered directly onto flat rectangular pads on the board surface using automated machinery.

Silk Screen

The printed graphic layer on a PCB that identifies component placements, labels, and track outlines.

Fuse

A safety device containing a calibrated conductive wire that melts and breaks the circuit when current exceeds its rating, protecting expensive components.

Voltage

The difference in electrical potential between two points in a circuit, measured in volts ($\text{V}$).

Current

The rate of flow of electric charge (electrons) past a given point in a circuit, measured in amperes ($\text{A}$).

Resistance

The degree to which a component or material opposes the passage of electric current, measured in ohms ($\Omega$).

Ohm's Law

The fundamental formula stating that voltage equals current multiplied by resistance: $V = I \times R$.

Electrical Power

The rate of electrical energy consumption or delivery, calculated as the product of voltage and current ($P = V \times I$) and measured in watts ($\text{W}$).

Continuance

A multimeter function (indicated by a diode symbol) that sounds an audible beep when there is a complete, unbroken conductive path between two points.

Resistor Colour Code

A standard system of colored bands on an axial resistor used to determine its resistance value, multiplier, and tolerance percentage.

Cell

A single electrochemical unit that generates electric potential, typically producing $1.5\,\text{V}$.

Battery

A direct current power source constructed from a combination of multiple interconnected electrochemical cells.

Batteries in Series

A configuration where batteries are connected end-to-end (positive to negative), causing their individual voltages to add together ($V_T = V_1 + V_2 + \dots$).

Batteries in Parallel

A configuration where identical batteries are connected positive-to-positive and negative-to-negative, maintaining supply voltage while increasing available current capacity.

Resistors in Series

A circuit arrangement where resistors are connected in a single line, with total resistance equal to the sum of individual values: $R_T = R_1 + R_2 + R_3 + \dots$.

Resistors in Parallel

A circuit arrangement where resistors share common connection nodes, with equivalent resistance calculated by: $\frac{1}{R_T} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \dots$.

AC Induction Generator

A machine that converts mechanical kinetic energy into three-phase alternating current ($\text{AC}$) electrical energy at high efficiency.

Transformer

An electrical device that uses mutual magnetic induction between primary and secondary wire coils on an iron core to step AC voltage up or down according to the turn ratio ($\frac{N_1}{N_2} = \frac{V_1}{V_2}$).

Full Bridge Rectifier

A bridge arrangement of four diodes that converts alternating current ($\text{AC}$) into pulsating direct current ($\text{DC}$) by steering both positive and negative half-cycles into a single direction.

Voltage Divider

A series arrangement of two or more resistors used to produce an output voltage that is a predictable fraction of the input voltage: $V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2}$.

LM7805

A linear integrated circuit voltage regulator designed to output a fixed, stable $5\,\text{V}$ DC supply from an unregulated higher input voltage.

LM317

An adjustable three-terminal positive linear voltage regulator IC capable of setting custom regulated output voltages via an external resistor network.

Potentiometer

A three-terminal variable resistor featuring an adjustable mechanical slider or wiper that forms a manually controllable voltage divider.

Analogue Signal

A continuous electrical signal whose voltage varies smoothly over time to represent continuously changing physical values.

Digital Signal

A discrete electrical signal that alternates strictly between two distinct voltage states ($0\,\text{V}$ and supply voltage), representing binary 0 and 1 (off and on).

Thermistor

A type of variable resistor whose electrical resistance changes in response to changes in ambient temperature.

Light Dependent Resistor (LDR)

A photo-sensitive variable resistor whose resistance decreases as the intensity of light shining on its surface increases.

Switch Poles

The number of separate moving conductors or independent circuits operated simultaneously by a single switch mechanism.

Switch Throws

The number of distinct closed output contact positions available to each pole of a switch.

Reed Switch

An electrical switch whose ferromagnetic contacts close and complete a circuit in the presence of an external magnetic field.

Mercury Switch

A tilt-activated switch consisting of a glass capsule containing a droplet of liquid mercury that bridges electrical contacts when tilted.

Diode

A two-terminal semiconductor component that allows electric current to flow in only one direction while blocking it in reverse.

Forward Bias

The operating condition of a diode where the anode is connected to positive voltage relative to the cathode, allowing current to flow freely.

Reverse Bias

The operating condition of a diode where higher potential is applied to the cathode than the anode, blocking current conduction.

Zener Diode

A specialized diode designed to conduct current in reverse bias once a specific breakdown threshold is reached, clamping the voltage at a constant level.

Bipolar Junction Transistor (BJT)

A three-terminal semiconductor device (Base, Collector, Emitter) used either as an electronically controlled switch or as a current amplifier.

NPN Transistor

A BJT whose emitter arrow points outwards ('Not Pointing iN'), which switches on when a small control signal of at least $0.7\,\text{V}$ is applied to the Base relative to the Emitter.

PNP Transistor

A BJT whose emitter arrow points inwards ('Pointing iN Purposefully'), which conducts when the Base is pulled to a lower potential than the Emitter.

Capacitor

A passive component composed of two conductive plates separated by an insulator that rapidly stores and releases electrostatic charge, blocking DC while allowing AC to pass.

Capacitive Smoothing

The use of a high-capacity capacitor connected in parallel with a rectified DC supply to discharge during voltage drops, smoothing out ripples into steady DC.

Decoupling Capacitor

A small-value capacitor placed in parallel between power rails and ground to filter out high-frequency electrical noise and transient spikes.

Capacitors in Parallel

A circuit arrangement where capacitors share positive and negative nodes, adding their capacitances directly: $C_T = C_1 + C_2 + C_3 + \dots$.

Capacitors in Series

A circuit arrangement where capacitors are connected end-to-end, with total capacitance calculated by the reciprocal formula: $\frac{1}{C_T} = \frac{1}{C_1} + \frac{1}{C_2} + \dots$.

Inductor

A passive electronic component consisting of a coiled wire that generates a magnetic field when electric current flows through it.

Electromagnet

An inductor formed by winding wire around a solid ferromagnetic core, creating a controllable magnetic field whose strength increases with current or turn count.

Solenoid

An electromechanical actuator consisting of an electromagnetic coil and a movable ferrous plunger that produces linear motion when energized and resets via a spring when unpowered.

Relay

An electrically operated mechanical switch using an internal electromagnetic coil to physically toggle contacts between normally open (NO) and normally closed (NC) terminals, enabling isolated control of high-power circuits.

Brushless DC Motor

A motor where the stator and rotor have no physical brush contacts, providing higher efficiency, speed, and quieter operation by sequentially energizing coil pairs via electronic driver circuitry.

Servo Motor

An actuator containing a DC motor, reduction gearing, and onboard feedback circuitry that allows precise control of angular shaft position via an input signal wire.

Stepper Motor

A brushless electric motor that divides a full rotation into a series of precise discrete angular steps with high holding torque, widely used in robotics, laser cutters, and 3D printers.