Transcript Project Guidance for Electronics

Project Guidance for
Electronics
What to do and what NOT to do
Introduction
• Your Project carries 30 % of the marks.
• You are to design and construct an electronic
artifact. This means an electronic circuit that does
something useful, rather than a circuit to illustrate
an electronic principle.
• Your project should last about 30 hours (10 weeks
@ 3 hours per week).
• It should be based on material you have studied in
Modules 1 and 2.
Aim
• To gain experience of managing a project.
• To use your skills in electronic design.
• To reinforce your skills and understanding
of electronics.
• To show that electronics is relevant to every
day problems.
• To get you to think like an electronic
engineer.
What You Need to Do
• You need to find something that you are interested
in.
• You need to be able to make it, so that it works.
• Keep it simple.
• Research at least TWO alternative circuits that
will do the job.
• Decide on which one you will make.
What you must NOT do
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Use powers greater than 100 watts.
Use Voltages bigger than 50 V.
Use a kit.
Use radio transmitters, transceivers, or rf
amplifiers.
• Make anything that would cause distress,
danger, or annoyance to others.
Help Available
• You are NOT expected to design from scratch.
• You are entitled to seek guidance from your
teacher.
• Guidance becomes assistance when the teacher
actually does something for you.
• You are allowed assistance, but that has to be
noted, and you cannot access that particular mark.
• However you may find it worth balancing the loss
of one mark against the gain of several others.
• So DON’T struggle on if stuck! ASK!
Specification
• You should specify at least three numerical
parameters from your research.
• Here is an example:
The amplifier gives a power output of 1
watt into a speaker of 8 ohms with an input
of 10 mV. The amplifier takes a quiescent
current of 5 mA from a 12 V battery.
Numerical parameters
Components
• Your project should be made of components that
are readily available.
• There is a large range of components available in
college.
• If the components are not available, you should
look them up in the catalogue with the reference
number and price. All prices exclude VAT which
needs to be added on.
• You find that the component you are after is not
available. There are equivalents that will do the
job. ASK!
• If you want a highly expensive component, then
you must pay for it yourself!
How to go about the Planning
You must have at least three active devices:
• Transistors or MOSFET
• Op-amp
• 555-timer
• Integrated circuits.
A circuit which has 4 NAND gates on one chip is
considered only to have ONE active device!
Electromagnetic relays and motors are NOT active
devices. The key thing to remember is that the
active device is a central process.
Calculations
• You need to consider at least two factors,
for example, how the resistance of an LDR
changes with light level, or the sound level
of an alarm.
• You should do calculations to show you for
example the powers of resistors that you
need. If your circuit gives these to you,
show how these are reached.
Development of the System
• You should develop your system as subsystems.
555-timer
Shift Register
with 3 flip-flops
Decoder
7 segment
display
• These should each be tested
separately before going to the next system
Building the Project
• You should develop the project on protoboard.
• You do NOT need to solder, nor should you worry
about PCB’s; you will not gain any extra marks
for this.
• You plan the layout of your circuit so that it is
clear and methodical.
• You might find it useful to develop one sub
system on one piece of breadboard.
• You should take photographs as you go along
Power
Supply
Inputs
Process
Output
Construction
• Work safely. Any “Ouch!” suggests otherwise.
• You must provide a risk assessment to help you
focus on safety.
• Take care not only of yourself and the equipment,
but also the components. The leads can break
easily. You can overheat components while
soldering.
• Do NOT spend time making a beautiful box for
your circuit. You will gain no extra marks for
doing so!
Testing
• You should test your project under normal
operating conditions.
• You must devise a testing plan BEFORE you start
testing.
• You should document your testing with
appropriate measurements laid out in tables and
graphs as appropriate.
• Compare your circuit with your original
specification.
• Modify your circuit if you need to.
Report
• Your report should be such that another AS level
student can pick up your report and reproduce the
circuit.
• You must provide evidence for all the marking
criteria if you are to gain the marks.
• You must maintain a record of supervision.
• Lay your report out in the same way as the
assessment scheme.
Writing Your Report
• You should word-process your report. If you
leave something out, you can add it later.
• Include photographs (JPEG images are sufficient).
However watch your file size!
• Write down your references, whether they are
from books or CD-ROM’s or the Internet.
• Include all your evidence. Credit cannot be given
unless the evidence is there.
Presenting Your Report
• You should write your report on A4.
• You should keep it brief and to the
point.
• You do not get extra marks for writing
loads! The project is not weighed!
• Staple your report together with the
cover sheets.
Spelling and Grammar
• Try to use good English. Although it is not
assessed, poor English takes away from the
impact of a report.
• Use your spell-check but don’t rely on it.
Yore spell cheque dose not all ways pick up every Miss Take
that ewe have maid. Even if their our know red lanes under
what you have wrote, it dose not mean that it make’s census.
And Finally…
Enjoy it!