Electronics study guides

A deep-dive WJEC A-Level Electronics guide to AC Circuits and Passive Filters. Covers peak, peak-to-peak and RMS values, capacitive and inductive reactance and how each varies with frequency, the phase between voltage and current, RC low-pass and high-pass filters, the cut-off frequency and minus 3 dB half-power point, gain in decibels and the Bode plot.

A deep-dive WJEC A-Level Electronics guide to Audio and Power Systems. Covers the audio signal chain, the mixer based on a summing amplifier, tone control with filters, voltage and power amplification, gain in decibels, driving a loudspeaker, and DC power supplies (transformer, rectification, smoothing with a reservoir capacitor, regulation, and electrical safety with fuses and earthing).

A deep-dive WJEC A-Level Electronics guide to Communications Systems. Covers the structure of a communication system, the need for a carrier, amplitude and frequency modulation, bandwidth and data rate, noise and distortion, radio-wave transmission and the aerial, attenuation, optical-fibre transmission by total internal reflection, and multimode versus monomode fibre.

A guide to WJEC A-Level Electronics Component 3, the Extended System Design and Realisation Task (non-exam assessment). Covers what the task asks (design, build, test and evaluate a working electronic system to a brief), the stages from specification to evaluation, how it draws on the core concepts and sub-systems, how it is assessed and weighted, and how to approach it for the most marks.

A deep-dive WJEC A-Level Electronics guide to the Core Concepts that underpin the whole qualification. Covers the systems approach and block diagrams, DC electrical circuits with Ohm's law, Kirchhoff's laws and the potential divider, and input and output sub-systems including sensors, transducers and drivers, with the equations and exam patterns WJEC repeats across both components.

A deep-dive WJEC A-Level Electronics guide to Instrumentation and Timing Systems. Covers sensors and the measurement chain, the Wheatstone bridge for resistive sensors, signal conditioning and the instrumentation amplifier, calibration, RC timing, the monostable and astable using the 555 timer, the period and frequency equations, and the generation of square waves and clock signals.

A deep-dive WJEC A-Level Electronics guide to Logic Systems. Covers the seven logic gates and truth tables, Boolean algebra and De Morgan's theorems, combinational design with sum-of-products and Karnaugh maps, NAND universality, and sequential logic with the SR latch, D-type and JK flip-flops, counters and shift registers.

A deep-dive WJEC A-Level Electronics guide to Microcontroller Systems. Covers the architecture of a microcontroller (CPU, memory, ports), digital input and output ports, interfacing switches, sensors and output devices, the on-chip ADC, and programming with flowcharts, the structures of sequence, selection and iteration, input and output instructions, time delays and subroutines.

A deep-dive WJEC A-Level Electronics guide to Operational Amplifiers. Covers the ideal op-amp and open-loop comparator, the Schmitt trigger and hysteresis, negative feedback with the inverting and non-inverting amplifiers and the virtual earth, the voltage follower, and the summing, difference and instrumentation amplifiers, with the gain equations and exam patterns WJEC repeats.

A deep-dive WJEC A-Level Electronics guide to Semiconductor Components. Covers n-type and p-type material and the p-n junction, the diode I-V characteristic and the rectifier, Zener, LED and photodiode, transistors as switches with cut-off and saturation and base-resistor design, and the common-emitter voltage amplifier with biasing and gain, plus the exam patterns WJEC repeats.

A deep-dive WJEC A-Level Electronics guide to Signal Conversion. Covers analogue-to-digital conversion (sampling, the Nyquist criterion and aliasing, quantisation, resolution, the number of bits and quantisation error) and digital-to-analogue conversion (the weighted-resistor summing DAC, the R-2R ladder DAC and reconstruction with a low-pass filter).