Wales Β· WJECSyllabus
Electronics syllabus, dot point by dot point
Every dot point in the Wales Electronicssyllabus, with a focused answer for each one. Click any dot point for a worked explainer, past exam questions, and links to related dot points. Written by Claude Opus 4.8, Anthropic's latest AI.
Component 1: Applications of diodes
Module overview β- How does a diode conduct one way only, and how is it used to protect a circuit and to rectify AC?The silicon diode and its one-way (rectifying) behaviour: using a diode to protect a circuit against reverse polarity and against inductive spikes, and half-wave rectification to convert AC into DC.9 min answer β
- How does a Zener diode hold a steady voltage, and how is it used to regulate a supply?The Zener diode and its reverse breakdown behaviour, and its use with a series resistor to provide a stable regulated output voltage.9 min answer β
Component 1: Circuit concepts
Module overview β- What are charge, current and voltage, and how do we measure them?Electric charge and current as the rate of flow of charge, the charge equation, voltage (potential difference) as energy per unit charge, standard circuit symbols, and the test equipment used to measure electrical quantities (multimeter, oscilloscope, logic probe).9 min answer β
- How do we calculate the electrical power dissipated by a component and the energy it transfers?Electrical power and energy, the power equations linking power to voltage, current and resistance, the energy equation, and using them to choose a suitable power rating for a component.9 min answer β
- How are voltage, current and resistance linked, and what do current-voltage graphs tell us?Resistance and Ohm's law, the equation linking voltage, current and resistance, and the current-voltage (I-V) characteristics of an ohmic resistor, a filament lamp and a silicon diode.9 min answer β
- How do current and voltage behave in series and parallel circuits?The current and voltage (potential difference) rules for series and parallel circuits, including the conservation of current at a junction and the sharing of voltage around a loop, and using them to analyse simple circuits.9 min answer β
Component 1: Combinational logic systems
Module overview β- How do we write logic as Boolean expressions, simplify them, and build any gate from NAND gates?Boolean expressions and the basic Boolean identities, simplifying combinational logic, building any logic function from NAND gates (NAND universality), and designing a logic system to meet a requirement using a data sheet to select ICs.9 min answer β
- What are the logic gates, and how do truth tables describe their behaviour?Logic levels (logic 1 and logic 0 as high and low), the NOT, AND, OR, NAND, NOR and XOR gates, their logic symbols, and constructing and using truth tables to describe combinational logic.9 min answer β
Component 1: Electronic systems and sub-systems
Module overview βComponent 2: Interfacing and control
Module overview β- What is a microcontroller, how is it interfaced, and how do flowcharts describe its program?The microcontroller as a programmable integrated circuit, how sensors and output devices are interfaced to it, designing and analysing a control program as a flowchart, and why microcontrollers are now used so widely.9 min answer β
- How does a Schmitt trigger clean up a noisy or slow signal, and how do we choose an interface?The Schmitt inverter and its switching with hysteresis, used to debounce switches and to give a clean digital output from a slow or noisy analogue input, and comparing transistors, comparators and Schmitt inverters as interface circuits.9 min answer β
Component 2: Operational amplifiers
Module overview β- What does an amplifier do, how is voltage gain calculated, and what are bandwidth and clipping?Amplification as increasing the voltage (or power) of a signal, the voltage gain equation, the gain-frequency response and bandwidth, and clipping distortion when the output is limited by the supply.9 min answer β
- How do inverting, non-inverting and summing op-amp circuits work, and how is a mixer built?The operational amplifier in inverting and non-inverting configurations and their gain equations, the summing amplifier (mixer) that adds several inputs, and the amplifier system block diagram from signal source to loudspeaker.10 min answer β
Component 1: Resistive components in circuits
Module overview β- How do an LDR and a thermistor turn light and temperature into a changing voltage?Input sensors as variable resistors: the light-dependent resistor (LDR) and the NTC thermistor, how their resistance varies with light and temperature, and using them in a potential divider so the output voltage responds to the physical quantity.9 min answer β
- How does a potential divider produce a chosen output voltage, and how do we design one?The potential divider: how two resistors share a supply voltage, the potential divider equation, and designing and analysing a divider to produce a required output voltage.10 min answer β
- Why do switches need pull-up or pull-down resistors, and how do we protect an LED with a series resistor?Pull-up and pull-down resistors that give a switch a defined logic level, and the current-limiting (series) resistor that protects an LED, including calculating its value.9 min answer β
- How do we calculate the total resistance of combined resistors and read a resistor's value and tolerance?Calculating the total resistance of resistors in series and in parallel, and identifying a resistor's value, tolerance and power rating from its colour code or the E24 preferred-value series.9 min answer β
Component 2: Sequential systems
Module overview β- How are D-type flip-flops connected to make a binary counter, and what is its timing diagram?Building a 1-bit and a 2-bit binary up-counter from rising-edge-triggered D-type flip-flops, how each stage divides the clock frequency by two, and reading the count from a timing diagram.9 min answer β
- How does a D-type flip-flop store and transfer a bit on a clock edge?The rising-edge-triggered D-type flip-flop: how it copies its D input to its Q output on the rising edge of the clock, its use as a data latch and for data transfer, and reading its behaviour from a timing diagram.9 min answer β
- How do decade counters, decoder/drivers, seven-segment displays and the 4017 produce a counting display or sequence?BCD and decade counters, the seven-segment display with its decoder/driver to show decimal digits, the 4017 decade counter as a sequencer with one output high at a time, and resetting a counter early to make a custom count length.10 min answer β
Component 1: Switching circuits
Module overview β- How does a voltage comparator switch at a threshold, and how do we interface it to an output?The voltage comparator as an integrated-circuit switching circuit that compares an input voltage with a reference, the use of a potential divider to set the reference and threshold, and interface circuits (including a relay or transistor driver) to switch an output.9 min answer β
- How do an npn transistor and an n-channel MOSFET act as electronic switches?The npn bipolar transistor and the n-channel enhancement MOSFET used as switches: how a small input controls a larger output current, the meaning of saturation and cut-off, and the differences between the two devices.9 min answer β
Component 3: Extended system design and realisation task
Module overview βComponent 2: Timing circuits
Module overview β- How does a 555 astable generate a continuous stream of pulses, and how do we find its frequency and mark-space ratio?The 555 timer in astable mode: how it produces a continuous square-wave output, the equations for frequency and period, and the meaning and calculation of the mark-space ratio.10 min answer β
- How does a 555 timer produce a single pulse of a set length?The 555 timer in monostable mode: how it produces a single output pulse of fixed duration when triggered, and the equation for the pulse duration in terms of the timing resistor and capacitor.9 min answer β
- How does a capacitor charge and discharge through a resistor, and how does this create a time delay?The capacitor and the resistor-capacitor (RC) network: how a capacitor charges and discharges through a resistor, the shape of the voltage-time curves, and how the RC combination produces a time delay.9 min answer β