# Use your results from b) to confirm Kirchhoffs current law

Do not use the duplicate resistor for Task 3.
a) Measure the actual EMF produced by the battery (2 marks).
b) Connect your multimeter as an ammeter (i.e. in series) and measure the total current from
the battery ( ), and also the current flowing through each resistor ( , , and ) (2 marks).
c) Use your results from b) to confirm Kirchhoffs current law (2 marks).
d) Calculate an equivalent single resistance which could replace R1–R3. Use this value to
calculate the expected total current, and compare this with the total current measured in b)
(2 marks).
e) Comment on your results (2 marks).
Task 4 – Maximum Power Transfer Theorem (10 marks)
Begin by constructing the above circuit, setting the source and load resistors to be your two
identical resistors.
a) Measure the battery voltage, the voltage across RS and RL and calculate the power dissipated
in each resistor (2 marks).
b) Replace the load resistor with each of your other three resistors, repeating the calculations
from part a) in each case (2 marks).
c) Comment on which load resistor allows the maximum power to be transferred, and the
efficiency of power transfer (2 marks).
d) Is ‘maximum power transfer the same as ‘maximum efficiency? Explain your answer
(4 marks).
Task 5 – Proteus simulation (10 marks)
a) Create a Proteus simulation3
as evidence (3 marks).
b) Use your simulation to repeat the chosen activity, recording all simulation results and
repeating all calculations (3 marks).
c) Discuss your findings, commenting on whether they agreed with theory, and with your
experimental results, accounting for any differences (4 marks).
3. Proteus simulation software is available in areas E + F of the David Goldman Informatics Centre. A
Proteus user guide for DC Circuits is available on SunSpace.
Task 6 – Written Report (30 marks)
You must produce an individual word processed report which gives evidence that you have
completed all required activities. This must be submitted online through SunSpace by 11.59 PM
Friday 5th February 2016.
Marks will be awarded for: –
a) Appropriate report structure, use of language and style (10 marks)
b) Effective use of IT (10 marks)
c) Linking of experimental results with theory, supported by appropriate references (10 marks)
Task 7 – Electrical Health and Safety (20 marks)
As part of the practical you have been asked to give an overview of the current UK standards and
approved codes of practice that should be observed when working in the electrical laboratory. The
activities a student would be expected to carry out in the laboratory include using testing and
measuring equipment that is supplied by the mains power. Your overview should also include a
“Code of Practice” which gives brief instructions to users of the lab on how to comply with the
standards. This section of your report should be no longer than 500 words.