Key term
CCEA A-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
Microelectronic Control SystemsOption A
Topic overviewMicrocontroller systems, ADCs and DACsStrain gauges and bridge circuitsOptical switches, encoded discs and Schmitt triggersOp-amp amplifiers and gainZener diodes and voltage regulatorsKarnaugh maps and binary countersSeven-segment, LCD and dot matrix displaysPIC flowcharts and programmingDC motors, stepper motors and driver circuits
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
Mechanical and Pneumatic SystemsOption B
Topic overviewHydraulics, system limitations and plant safetyTorque, work, power and air consumptionVacuum handling, proximity sensors and 5/3 valvesSequential and cascade pneumatic circuitsCam profiles and follower displacement diagramsGear geometry, pulley blocks and ratchetsToggles, treadles, shafts and couplingsFriction, brakes and clutchesBearings, lubrication and seals
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 Design in Industry and SocietyOption C
Topic overviewLife-cycle environmental impact and climate changeThe 6Rs, waste and environmental legislationSustainable metals, plastics and degradable polymersProduct life cycles, consumer types and relaunchesCAD, CAM, 3D scanning and quick-change mouldingMarket pull, technology push and market strategyPrice, place and promotionJigs, fixtures and ICT in quality controlDesign for maintenance, inclusion and scale productionRendering, typography and presentationDyson, Baylis, Memphis and Apple
Product Development
Product and System Design and Manufacture
Electronic Control Systems
Switches, pull-up and pull-down resistors
- 3 things to know
- AS 1 Paper 2
Overview
Poles 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.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What does an SPDT switch do?
Key term
Explain how a DPDT switch can reverse a DC motor.
Questions from this subtopic
Each one with the model answer underneath.
- 1
What do the terms pole and throw mean for a switch?
Model answer
The number of poles is the number of separate circuits a switch controls. The number of throws is the number of positions each pole can connect to.
- 2
What does an SPDT switch do?
Model answer
A single pole double throw switch connects one common terminal to either of two outputs. The switch changes a circuit over, such as selecting one of two LEDs.
- 3
Explain how a DPDT switch can reverse a DC motor.
Model answer
A DPDT switch has two linked poles that change over together. Wired crosswise, the poles swap the motor's connections to the supply and so reverse its direction.
- 4
What is the difference between a push-to-make and a push-to-break switch?
Model answer
A push-to-make switch closes the circuit only while it is pressed. A push-to-break switch opens the circuit only while it is pressed.
- 5
Suggest a use for a push-to-break switch.
Model answer
A fridge door switch is push-to-break. The closed door holds the button in, and an open door releases it to switch the light on.
- 6
How does a reed switch work?
Model answer
A reed switch has two thin metal contacts sealed inside a glass tube. A nearby magnet pulls the contacts together, closing the circuit.
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The same content, four other ways.
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