WJEC GCSE Electronics: electronic systems and sub-systems overview

The electronic systems and sub-systems content of WJEC Eduqas GCSE Electronics is the foundation of Component 1 (Discovering Electronics). It teaches you to treat any electronic product as a system built from sub-systems: an input (sensing) stage, a process stage and an output stage. This page maps the content and links to the focused answer page.

What the topic covers

The systems approach asks you to split a product into blocks by job, draw a system block diagram with arrows showing the signal flow, recognise the common building blocks of each stage, and explain how the stages connect.

Input (sensing) sub-systems

Sensors that turn a physical change into a voltage: an LDR for light, a thermistor for temperature, a microphone for sound, plus pressure, moisture, magnetic and movement sensors, usually used in a potential divider.

Process sub-systems

Blocks that decide what to do with the signal: logic gates, comparators, latches, counters and timing (time-delay) circuits.

Output sub-systems and transducer drivers

Output transducers such as lamps, LEDs, buzzers, loudspeakers, motors and solenoids, and the transistor or MOSFET transducer driver placed between the process and a high-current output.

See the focused page: Electronic systems and sub-systems.

How this content is examined

This content sits in Component 1 (Discovering Electronics), a written paper of 1 hour 30 minutes worth 40% of the GCSE. Expect to draw or complete a system block diagram, name suitable input, process and output sub-systems for a described product, classify devices as input or output transducers, and explain why a transducer driver is needed. The systems language is then reused throughout both written papers, because every circuit you study is a sub-system that fits into a larger system.

How to study it

1. Always think in three boxes. For any product, ask what it senses (input), what decision it makes (process) and what effect it produces (output).
2. Draw arrows, not just boxes. A block diagram must show the direction of signal flow.
3. Name blocks for the task. Use "light sensor", "comparator", "motor", not vague labels.
4. Separate input and output transducers. Sensors convert physical to electrical; lamps, buzzers and motors convert electrical to physical.
5. Remember the driver. A logic or comparator output cannot drive a motor or relay directly; include a transistor or MOSFET driver.

For the official specification

WJEC Eduqas publishes the full GCSE Electronics specification, past papers and mark schemes at wjec.co.uk. Always revise from the current specification and the board's own past papers, because question style and the printed equation and symbol lists are board-specific.