WBCHSE HS Vocational Electronics key terms

The rate at which electric charge flows past a point in a circuit, measured in amperes. One ampere equals one coulomb of charge passing each second.

The work needed to move a unit charge between two points in a circuit, measured in volts. It is the electrical 'push' that drives current through a component.

The opposition a component offers to the flow of current, measured in ohms. It converts electrical energy into heat and depends on material, length, and cross-sectional area.

The relationship stating that current through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance, written as V equals I times R.

A standard system of coloured bands printed on a resistor to indicate its resistance value and tolerance, with each colour representing a digit or multiplier.

The permissible variation of a component's actual value from its marked value, usually given as a percentage. A 100-ohm resistor with 5 percent tolerance may lie between 95 and 105 ohms.

A component that stores electric charge in an electric field between two conducting plates separated by a dielectric. Its capacitance is measured in farads.

A coil of wire that stores energy in a magnetic field when current flows through it. Its inductance is measured in henries and it opposes changes in current.

A circuit in which components are connected end to end so the same current flows through each. The total resistance is the sum of the individual resistances.

A circuit in which components are connected across the same two points so each has the same voltage. The total resistance is always less than the smallest branch resistance.

A material whose conductivity lies between that of a conductor and an insulator, and which increases when doped or heated. Silicon and germanium are common examples.

The boundary formed when p-type and n-type semiconductor regions meet. It conducts easily in one direction and blocks the other, creating a depletion region.

The thin zone around a PN junction where mobile charge carriers have diffused away, leaving fixed ions. It acts as a barrier that must be overcome for conduction.

A two-terminal semiconductor device that allows current to flow mainly in one direction. It is used for rectification, protection, and signal detection.

The condition in which the p-side of a diode is made positive relative to the n-side, narrowing the depletion region and allowing substantial current to flow.

The condition in which the p-side of a diode is made negative relative to the n-side, widening the depletion region and blocking current except for a tiny leakage current.

A circuit that converts alternating current into pulsating direct current using diodes. It may be half-wave, using one diode, or full-wave, using two or four.

A specially doped diode designed to operate safely in reverse breakdown at a defined voltage. It is used to regulate or stabilise voltage in power supplies.

A three-terminal semiconductor device used to amplify or switch signals. In a bipolar junction transistor the terminals are emitter, base, and collector.

Setting the steady direct-current voltages and currents at a transistor's terminals so it operates in the desired region, such as active, cut-off, or saturation.

The ratio of output current to input current in a transistor, denoted beta or hFE for a bipolar device. It indicates how strongly the device amplifies current.

A circuit that increases the amplitude of a signal without changing its waveform. Its performance is described by gain, bandwidth, input impedance, and output impedance.

Returning a portion of a circuit's output to its input. Negative feedback reduces gain but improves stability, bandwidth, and distortion; positive feedback can cause oscillation.

A basic digital circuit that performs a Boolean operation on one or more inputs to produce a single output, such as AND, OR, NOT, NAND, or NOR.

A table listing every possible combination of inputs to a logic circuit alongside the corresponding output, used to define and verify its behaviour.

A branch of mathematics using variables that take only the values 0 and 1, with operations AND, OR, and NOT. It is used to simplify digital logic expressions.

A digital circuit with two stable states that stores one bit of data. It changes state only when triggered by a clock or control input.

A test instrument that measures voltage, current, and resistance, and often continuity or diode drop. It may be analogue with a moving pointer or digital with a display.

An instrument that displays signal voltage against time on a screen, allowing measurement of amplitude, frequency, phase, and waveform shape.

The number of complete cycles of a periodic signal occurring each second, measured in hertz. It equals the reciprocal of the time period.

A circuit that holds its output voltage nearly constant despite changes in input voltage or load current. Common types include zener-based and three-terminal integrated regulators.

A capacitor connected across a rectifier's output to smooth the pulsating direct current into a steadier voltage by charging and discharging with each cycle.

A circuit that generates a continuous periodic output signal without an external input signal, using positive feedback and a frequency-determining network.

The process of varying a property of a high-frequency carrier wave, such as its amplitude or frequency, in accordance with an information signal.

A high-frequency continuous wave that is modulated by an information signal and then transmitted. Its frequency is much higher than that of the message.

A conducting structure that radiates or receives electromagnetic waves. Its length is usually related to the wavelength of the signal it handles.

A single integrated circuit containing a processor, memory, and input/output peripherals, programmed to control devices and processes in embedded systems.

A dedicated computer built into a product to perform a specific control task, usually with limited memory and real-time constraints.

A small, fast storage location inside a processor that holds data or an address during an operation. Its size is usually the processor's word length.

A reusable board with interconnected holes for building and testing circuits without soldering. Rows of holes are internally linked in a fixed pattern.

Joining metal parts with a low-melting alloy to make an electrical and mechanical connection. Good joints are shiny and smooth, not dull or ball-shaped.

A check using a multimeter to confirm that a low-resistance path exists between two points, often signalled by a beep. It detects breaks and short circuits.

A drawing that uses standard symbols to show how components are connected electrically, without regard to their physical layout on a board.

A written account of a student project covering the aim, circuit design, components used, construction, testing results, and conclusions drawn from the work.