Process
CCEA AS-Level Technology and Design 8900
Material Selection and Wood
Metals
Plastics
Composite and Emerging Materials
Processing Materials
Product Analysis and Design Communication
Design for Manufacture, Quality and Safety
Electronic Control SystemsOption A
Topic overviewControl systems, feedback and electronics safetyResistors, Ohm's law and power ratingsCapacitors and RC timingPotential dividers, sensors and comparatorsSwitches, pull-up and pull-down resistorsOutput devices and LEDsTransistors, Darlington pairs and thyristorsLogic gates, truth tables and flip-flops555 monostable and astable timers
Mechanical and Pneumatic ComponentsOption B
Topic overviewOpen and closed loop mechanical and pneumatic controlSafe working with compressed air and mechanismsLevers, linkages and momentsGear types and gear trainsPulleys, belts, chains and shaft fixingsCams, cranks and converting motionCompressed air supply and pneumatic valvesCylinders, shuttle valves, restrictors and reservoirsPneumatic circuits for logic, timing and speed control
Designing and Manufacturing ProductsOption C
Topic overviewResearch, questionnaires and specificationsIdea generation, critiques and computer simulationManufacturing planning and product evaluationCFRP, GRP, Kevlar and tungsten carbideSmart materials, nanotechnology and biophotovoltaicsIsometric, perspective and assembly drawingLaminating, steam bending, cutting and printing processesRisk assessment and product safety lawScales of production, JIT and cell productionQuality assurance, ISO 9001 and continuous improvementDesign influences and intellectual property rights
Product Development
Electronic Control Systems
- 9 subtopics
- 27 things to know
- AS 1 Paper 2
- Option A, Electronic and Microelectronic Control Systems
What Electronic Control Systems covers
Electronic Control Systems is examined in Unit AS 1, Paper 2: Option A, Electronic and Microelectronic Control Systems, one option of three. It covers control systems, feedback and electronics safety, resistors, Ohm's law and power ratings, capacitors and RC timing, potential dividers, sensors and comparators, switches, pull-up and pull-down resistors, output devices and LEDs, transistors, Darlington pairs and thyristors, logic gates, truth tables and flip-flops and 555 monostable and astable timers.
Where it is assessed
AS 1 Paper 2
Option A, Electronic and Microelectronic Control Systems — a written examination.
Check the CCEA specification ↗The 9 subtopics
Each one has its own page. CCEA AS Technology and Design students sit this topic in the first year.
- Control systems, feedback and electronics safetyInput, control and output, on/off and continuous control, open and closed loop systems, feedback, circuit symbols, and safe practice when building and testing circuits.Open →
- Resistors, Ohm's law and power ratingsThe resistor colour code and tolerance, the E12 series, Ohm's law and power with worked calculations, power ratings, and series and parallel combinations.Open →
- Capacitors and RC timingElectrolytic and non-polarised capacitors, voltage ratings, the RC time constant with worked delays, charging and discharging graphs, and RC timers with transistors.Open →
- Potential dividers, sensors and comparatorsThe potential divider equation with worked outputs, LDRs and thermistors in dark, light and frost sensors, variable resistors, and comparators with reference voltages.Open →
- Switches, pull-up and pull-down resistorsPoles and throws, SPDT and DPDT switches, push-to-make and push-to-break, reed switches and microswitches, AND and OR switch arrangements, and pull-up and pull-down resistors.Open →
- Output devices and LEDsLED series resistors with worked values, LEDs against lamps, current calculations for heaters and solenoids, relays and latching relays, solenoid valves, buzzers and piezo sounders.Open →
- Transistors, Darlington pairs and thyristorsTransistor switching and hFE, base resistor and Ic(max) calculations, Darlington pairs and their gain, protective diodes on relay coils, and thyristors in alarms.Open →
- Logic gates, truth tables and flip-flopsAND, OR, NOT, NAND, NOR, EOR and ENOR gates, universal gates, logic for heaters and alarms, SR flip-flops from NAND gates, and PICs against hardwired logic.Open →
- 555 monostable and astable timersThe 555 monostable and astable, pulse length and frequency equations with worked values, period and frequency, mark/space ratio and typical applications.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Analyse an automatic night light in terms of input, control and output.
Key term
What is the E12 series?
Key term
A 1 kΩ resistor is in series with two 2 kΩ resistors in parallel. What is the total resistance?
Key term
What do COM, NO and NC mean on a relay's contacts?
Numbers
A 555 monostable must give a 10 s pulse using a 100 μF capacitor. Calculate R.
Key term
What does a capacitor do in a circuit?
Key term
What is a potential divider?
Key term
What do the terms pole and throw mean for a switch?
Key term
How does an npn transistor act as a switch?
Key term
Describe the output of an AND gate.
Key term
How does an electrolytic capacitor differ from a non-polarised capacitor?
Key term
State the potential divider equation.
Key term
What does an SPDT switch do?
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Why must an LED always have a series resistor?
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What base–emitter voltage turns a silicon transistor on?
Key term
Describe the output of an OR gate.
Key term
What does a 555 monostable circuit do?
Key term
What is the difference between on/off control and continuous control?
Key term
How does the four-band colour code give a resistor's value?
Key term
Describe a non-polarised capacitor and where it is used.
Numbers
Calculate Vₒᵤₜ for a 9 V supply with R₁ = 10 kΩ and R₂ = 5 kΩ.
Key term
Explain how a DPDT switch can reverse a DC motor.
Numbers
Calculate the series resistor for an LED on 9 V, with a forward voltage of 2 V and a maximum current of 20 mA.
Key term
Define the current gain hFE of a transistor.
Key term
What does a NOT gate do?
Key term
How is a 555 monostable triggered?
Take Electronic Control Systems further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Push-to-make switch vs Push-to-break switch
Push-to-make switch: a momentary contact that completes the circuit only while pressed. Push-to-break switch: a momentary contact that opens the circuit only while pressed.
Pull-up resistor vs Pull-down resistor
Pull-up resistor: a component holding a logic input at 1 until a contact closes to 0 V. Pull-down resistor: a component holding a logic input at 0 until a contact closes to the positive supply.
Electrolytic capacitor vs Non-polarised capacitor
Electrolytic capacitor: a large-value charge store that must be fitted the correct way round. Non-polarised capacitor: a small-value charge store that can be fitted either way round.
Questions from this topic
Each one with the model answer underneath.
- 1
What are the three stages of an electronic system?
Model answer
An electronic system has an input stage, a control or process stage and an output stage. The input senses a change and the process decides the response. The output then acts on the surroundings.
- 2
Analyse an automatic night light in terms of input, control and output.
Model answer
A light-dependent resistor in a potential divider is the input that senses darkness. A transistor switch forms the control stage. The lamp or LED is the output.
- 3
What is the difference between on/off control and continuous control?
Model answer
On/off control has only two output states, fully on or fully off, as in a thermostat switching a heater. Continuous control varies the output smoothly over a range, as a dimmer varies lamp brightness.
- 4
What is an open loop control system?
Model answer
An open loop system has no feedback, so its output is never checked against what is wanted. A toaster running on a fixed timer is an example.
- 5
What is a closed loop control system?
Model answer
A closed loop system uses a sensor to monitor its own output. The controller corrects any difference between the actual output and the desired output.
- 6
What is feedback in a control system?
Model answer
Feedback is information about the output that is returned to the controller. The system uses feedback to adjust its output towards the desired value.
What is inside Levo
Six ways to work the same material.
Electronic Control Systems revision questions
- Is Electronic Control Systems examined at AS in CCEA Technology and Design?
- Yes. It sits in AS 1 Paper 2, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.
- What does Electronic Control Systems cover in CCEA AS-Level Technology and Design?
- 9 subtopics: control systems, feedback and electronics safety, resistors, ohm's law and power ratings, capacitors and rc timing, potential dividers, sensors and comparators, switches, pull-up and pull-down resistors, output devices and leds, transistors, darlington pairs and thyristors, logic gates, truth tables and flip-flops and 555 monostable and astable timers. Each one has its own page with questions and model answers.
- How is Electronic Control Systems organised?
- By the CCEA 8900 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Electronic Control Systems, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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