Electronic systems: the input, process and output model, sensors as inputs, processing with transistors and microcontrollers (including programmable control), and outputs such as LEDs, buzzers and motors.

What this dot point is asking

OCR J310 expects you to understand electronic systems at a systems level: the input, process, output model, the role of sensors as inputs, processing with transistors and microcontrollers, and common outputs. The big idea is that thinking in systems blocks makes electronics designable without tracing every wire. In the written exam this is tested by mapping components to the three stages and by explaining the advantages of programmable control.

The input, process, output model

Thinking in blocks lets a designer plan a product's behaviour without worrying about every component at first: decide what it must sense, what it must do, and what it must produce, then choose components for each block. This is the same model used when selecting electronic components.

Inputs and sensors

A sensor turns a physical condition (light, heat, movement) into an electrical signal the process block can use.

Processing: transistors and microcontrollers

A simple product can process with a transistor (switch the output when it gets dark). A more capable product uses a microcontroller, whose advantages are:

• Fewer components: one programmable chip can replace many fixed parts, so the circuit is smaller, cheaper and simpler.
• Flexibility: the same hardware can be reprogrammed to change or add functions without redesigning the circuit.
• Complex behaviour: timing, counting, patterns and decisions are easy in software.

Outputs

Try this

Q1. Name the three blocks of an electronic system. [3 marks]

• Cue. Input, process, output.

Q2. State one advantage of using a microcontroller instead of many fixed components. [1 mark]

• Cue. Fewer components (smaller, cheaper, simpler) or it can be reprogrammed to change function.