Electrical Systems Lecture Flashcards

A comprehensive set of vocabulary flashcards covering the components, measurements, types, safety features, and energy calculations of electrical systems.

Electric Cells / Batteries

Portable sources of electricity that convert chemical potential energy into electrical energy.

Electric Circuit

The path along which the electric current moves, formed by joining electrical components together.

Closed Circuit

An electrical path joined without any gaps, allowing electricity to flow from one end of the battery to the other.

Open Circuit

An incomplete circuit through which electricity cannot flow.

Electric Current ($I$)

The rate of flow of electric charges, measured in ampere ($A$) using an ammeter connected in series.

Electron Flow

The actual movement of charge carriers where electrons flow from the negative terminal to the positive terminal of a battery.

Conventional Current

A scientific convention where positive charges are assumed to flow from the positive terminal to the negative terminal of a battery.

Potential Difference ($V$)

The amount of work done to drive a unit charge through a component, measured in volts ($V$) using a voltmeter connected in parallel.

Electrical Resistance ($R$)

A measure of how much an electrical component opposes the flow of electric current, measured in ohms ($\Omega$).

Resistance Formula

The calculation for resistance defined by the ratio $R = \frac{V}{I}$ where $V$ is potential difference and $I$ is current.

Electrical Conductors

Materials with low electrical resistance, such as copper or silver, that allow current to flow easily.

Electrical Insulators

Materials with very high electrical resistance, such as plastics or rubber, that do not allow current to flow through.

Fixed Resistor

An electrical component with a specific resistance value that cannot be changed.

Variable Resistor (Rheostat)

A device where the resistance value can be adjusted, often by using a slider to change the length of wire the current flows through.

Series Circuit

A circuit arrangement with only one path for charges to flow; resistance increases and current decreases as more resistors are added.

Parallel Circuit

A circuit arrangement with more than one path for charge flow; total resistance decreases and current increases as more resistors are added.

Nichrome

A material with high resistance used in heating elements because it can withstand high temperatures when current passes through.

Tungsten

A material with high resistivity and a high melting point of approximately $3400\,^{\circ}\text{C}$ used as filament in lamps.

Live Wire

The brown wire in a system connected to high voltage that delivers current to an appliance; it is where switches and fuses are connected.

Neutral Wire

The blue wire that completes the circuit by providing a returning path to the power supply at zero voltage.

Earth Wire

A yellow and green safety wire with low resistance connected to the metal casing of appliances to lead current to the ground during a fault.

Circuit Breaker

A safety device connected to the live wire that switches off electrical supply during excessive current flow and can be reset.

Fuse

A safety device containing a thin wire that melts and opens the circuit if current is too large; it must be replaced after it blows.

Three-Pin Plug

The standard plug used in Singapore containing a cartridge fuse, earth wire, live wire, and neutral wire for safety.

Double Insulation

A safety feature in appliances with non-metallic casings where internal components are insulated from the outer casing, typically used with two-pin plugs.

Electrical Power

The amount of electrical energy used for conversion to other forms of energy per unit time, measured in watts ($W$).

Kilowatt-hour ($kWh$)

The unit for total electrical energy consumption calculated as $\text{Power (kW)} \times \text{Time (h)}$.

Ohm's Law

A fundamental law stating that $V = I \times R$, where $V$ is voltage, $I$ is current, and $R$ is resistance.