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Northern IrelandTechnology and Design

AS 1 Electronic and Microelectronic Systems

7 dot points across 7 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do sensors and potential dividers turn a physical quantity into a usable input voltage?

Input transducers (LDR, thermistor, switches) and the potential divider as a sensing subsystem.
A CCEA A-Level Technology and Design answer on input transducers such as the LDR, thermistor and switches, and how a potential divider converts a changing resistance into a changing voltage for the process subsystem to act on.
12 min answer →

How do logic gates make decisions, and how do we describe and combine them?

Logic gates (AND, OR, NOT, NAND, NOR, EOR), truth tables, Boolean expressions and combinational logic for decision-making.
A CCEA A-Level Technology and Design answer on the function of AND, OR, NOT, NAND, NOR and EOR gates, their truth tables and Boolean expressions, and combining gates into decision-making combinational logic systems.
12 min answer →

How does an operational amplifier compare two voltages and amplify a signal?

The operational amplifier as a comparator and as an inverting/non-inverting amplifier, with gain and the use of a reference voltage.
A CCEA A-Level Technology and Design answer on the operational amplifier used as a comparator that switches when a sensor voltage crosses a reference, and as an inverting or non-inverting amplifier with calculable gain.
12 min answer →

How are output transducers driven and protected by the process subsystem?

Output transducers (LED, lamp, buzzer, motor, relay, solenoid), current-limiting resistors and driver/interface circuits.
A CCEA A-Level Technology and Design answer on output transducers such as LEDs, lamps, buzzers, motors, relays and solenoids, calculating the LED current-limiting resistor, and using transistor and relay driver circuits to interface high-power loads to logic.
12 min answer →

How does the input-process-output model let us design electronic systems as blocks?

The systems approach: input, process and output subsystems, block diagrams, signal flow and feedback.
A CCEA A-Level Technology and Design answer on the systems approach to electronics, modelling a circuit as input, process and output subsystems with block diagrams, signal flow, the system boundary and feedback.
11 min answer →

How does a transistor act as an electronic switch driven by a small signal?

The bipolar transistor and MOSFET as switches, base/gate biasing, the Darlington pair and switching inductive loads.
A CCEA A-Level Technology and Design answer on using a bipolar transistor or MOSFET as an electronic switch, base and gate biasing, current gain and the Darlington pair, and protecting against the back-e.m.f. of an inductive load with a flyback diode.
12 min answer →

How do RC timing and the 555 timer produce delays and oscillations?

The capacitor-resistor time constant, and the 555 timer in monostable and astable modes.
A CCEA A-Level Technology and Design answer on RC timing and the time constant, and the 555 timer IC configured as a monostable (one-shot delay) and an astable (oscillator), with the equations for pulse length and frequency.
12 min answer →