1.   Electronics has undergone rapid development due to greater knowledge of the properties of materials and increasingly complex manufacturing techniques

Students learn to:

•    identify that early computers each employed hundreds of thousands of transistors

•    explain that the invention
of the integrated circuit using a silicon chip was related
to the need to develop lightweight computers and compact guidance systems

•    explain the impact of the development of the silicon chip on the development
of electronics

•    outline the similarities
and differences between
an integrated circuit and
a transistor

Students:

•    identify data sources,
gather, process and analyse information to outline the rapid development of electronics and, using examples, relate this to the impact of electronics on society

•    gather secondary information to identify the desirable optical properties of silicon, including:

      –    refractive index

      –    ability to form fibres

      –    optical non-linearity

2. Electronics use analogue and digital systems, the basic circuit elements of which are potential dividers and transistors

•    describe the difference between an electronic circuit and an electric circuit and the advantages and disadvantages of each

•    distinguish between digital and analogue systems in terms of their ability to respond to or process continuous or discrete information

•    identify systems that are digital and ones that are analogue in a range of devices

•    identify potential dividers and transducers as common elements in both analogue and digital systems

•    explain how the ratio of resistances in a potential divider allows a range of voltages to be obtained

•    describe the role of transducers as an interface between the environment and an electronic system

•    identify data sources, perform an investigation to demonstrate the difference between digital and analogue voltage outputs over time

•    gather, process and present information to identify electronic systems that use analogue systems, including television and radio sets and those that use digital systems, including CD players

•    solve problems and analyse information involving resistances, voltages and currents in potential dividers

3.   Sensors and other devices allow the input
of information
in electronic systems

Students learn to:

•    define a transducer as a device that can be affected by or affect the environment

•    explain the relationship in
a light-dependent resistor (LDR) between resistance and the amount of light
falling on it

•    describe the role of LDRs
in cameras

•    explain why thermistors
are transducers and describe the relationship between temperature and resistance in different types of thermistors

•    distinguish between positive and negative temperature coefficient thermistors

•    explain the function of thermistors in fire alarms and thermostats that control temperature

Students:

•    gather, process and present graphically information on
the relationship between resistance and the amount
of light falling on a light-dependent resistor

•    solve problems and analyse information involving circuit diagrams of LDRs and thermistors

•    gather and analyse information and use available evidence to explain why solar cells, switches and the light meter in a camera may be considered input transducers

4. Some devices use output transducers to make connections between the product and the environment

•    explain the need for a relay when a large current is used in a device

•    describe the role of the electromagnet, pivot, switch contacts and insulator in a relay

•    describe the structure of light-emitting diodes (LEDs) in terms of p-type and n-type semiconductors

•    explain why voltmeters, ammeters, CROs and other electronic meters are considered output transducers

•    process information to explain the way in which a relay works using a circuit diagram

•    solve problems and analyse information using circuit diagrams involving LEDs and relays

•    analyse information to assess situations where an LED would be preferable to an ordinary light source

5.    Information can be processed using electronic circuits

Students learn to:

•     describe the behaviour of the logic gates in terms of the high and low voltages and relate these to input and outputs

•     explain the difference between a difference and a parity gate

•     identify that gates can be used in combination with each other to make half or full adders

Students:

•    identify data sources, plan, choose equipment or resources for, and perform first-hand investigations to construct truth tables for
logic gates

•    solve problems and analyse information using circuit diagrams involving logic gates

6. Amplifiers are used in different ways in current technologies

•     describe the functions and the properties of an ideal  amplifier

•     identify the voltage over which the amplifier acts as a linear or analogue device and a digital device

•     describe how amplifier can be used as amplifying circuits

•     explain that the gain of an amplifier is related to the ratio of its output voltage to its input voltage:

•     define open loop gain:

•     explain the difference between the non-inverting input and the inverting input

•     discuss how a control system can be used to provide feedback

•    solve problems and analyse information to show the transfer characteristics of an amplifier

•    gather and present graphical information to distinguish between the input and output voltages when the voltages are applied to the inverting and non-inverting inputs respectively

•    solve problems and analyse information using:

     and

•    gather information to identify the different ways in which amplifiers are used in current technologies

7. There are physics limits that may impact on the future uses of computers

•     identify that the increased speed of computers has been accompanied by a decrease in size of circuit elements

•     explain that as circuit component size is decreasing, quantum effects become increasingly important

•    gather, process and analyse information and use available evidence to discuss the possibility that there may be a limit on the growth of computer power and this may require a reconceptualisation of the way computers are designed