GCSE Electronics and Control Systems Notes

Mechanisms

Worm and wheel gear

BenefitsDisadvantages

The worm can turn the pinion but the pinion cannot turn the worm locking action Good mechanical advantage Good accuracy Stays where you put it.

Worm and wheel materials are expensive Produces a lot of heat

Nut and Bolt

Purpose To lock mechanism on the desired place (shaft)

Why do engines need oil?

The oil lubricates the mechanism To reduce the amount of friction Cools down the mechanismDrip feed

A container containing oil placed on top of a mechanism as oil drips onto it.Why is a drip feed used to deliver the oil? Provides a continuous however limited supply of oil

Sustainable design

Materials:Softwood

AdvantagesDisadvantages

Can be recycled More sustainable than hardwoods Lower cost High strength under compression Easily flammable Needs protection from water/damp Prone to attack from insects/termites.

Hardwood

AdvantagesDisadvantages

Exotic/desirable aesthetic Generally more durable Used for expensive furniture/fittings More expensive take longer to grow Leads to a greater risk of deforestation

Plastic

AdvantagesDisadvantages

Low cost Can be easily moulded Extremely versatile huge range of plastic with different properties Takes a long time to decay Must be sorted when recycling time consuming Made from oil non-renewable source

Aluminium

AdvantagesDisadvantages

Does not rust Very ductile Easy to recycle recycled aluminium used 80% less energy to make Comes from bauxite non-renewable source High energy consumption when producing new aluminium

Steel

AdvantagesDisadvantages

Easy to recycle and sort from other metals (magnetic) Very strong Can be made into different types of steel - depending on carbon content May be more expensive compared to other structures Could corrode if frequently exposed to air or water (e.g. bridges)

The 6RsRecycle using a product of parts of a product again if possible but sometimes the product might be reprocessed in some way in order for it to be reused.

3 types of recycling: Primary second hand use of items Secondary the materials from product of parts of a product is used again Tertiary products are broken down and reformulated

Reuse products that are used again result in less waste. Some product may have parts which could be adapted for different uses.Upcycling using an unwanted product and making it into something better.

Reduce when designing new products, designers need to consider whether the product is sustainable based on the materials, manufacturing and how it is used.Refuse Processing, manufacturing, packaging and transport of products uses a high amount of energy and creates a lot of waste. Environmental and social factors need to be considered.Re-think As resources become scarce, we need to rethink of reasons why we buy products and the way in which we use energy. Designers need to rethink their designs so they are less harmful to the environment.Repair Many products are not designed to be repaired and are often cheaper to buy than repair. Some products are difficult to get replacement parts.

Things to consider

RecycleReuseReduceRefuseRethinkRepair

Can different materials be separated easily? It is made from lots of different materials? Does it take a lot of energy to reprocess? Does it have another valuable uses without reprocessing it? Are there parts that can be recycled? Are there parts that are not needed? Could it be made with less material? Could it use less energy? Is the product going to last? Are there materials which are not sustainable? How can it do its job better? Can it be redesigned to make it better? How easy is it to replace parts? Could be repaired or designed to be a throwaway?

Energy

Electricity is made using a generator where a magnet turns inside a coil of wire There are different methods in making a magnet turn; some uses a steam turbine and some turn the generator directly using fan blades When a steam turbine is used, the heat source that creates the steam determines the method of generation. Some generating electricity are renewable while some are non-renewable.Non-renewableRenewable

These methods use fuels that will run out.These will not run out.

Fossil fuels (coal, oil, natural gas, nuclear, shale gas) Solar, wind, hydroelectric, tidal waves, geothermal biomass