Assignment front sheet
Learner name / Assessor name
Paul Lewis
Date issued / Completion date / Submitted on
28/2/11 / 17/3/11
Qualification / Unit number and title
BTEC National Diploma in Engineering / Unit 6, Electrical and Electronic Principles
Assignment title / DC Networks
In this assessment you will have opportunities to provide evidence against the following criteria.
Indicate the page numbers where the evidence can be found.
Criteria reference / To achieve the criteria the evidence must show that
the student is able to: / Task no. / Evidence
P1 / Use DC circuit theory to calculate current, voltage and resistance in DC networks
P2 / Use a multimeter to carry out circuit measurements in a DC network
M1 / Use Kirchoff’s laws to determine the current in various parts of a network having four nodes and the power dissipated in a load resistor containing two voltage sources
Learner declaration
I certify that the work submitted for this assignment is my own and research sources are fully acknowledged.
Learner signature: Date:
Assignment brief
Qualification / BTEC National Diploma in Engineering
Unit number and title / Unit 6 Electric and Electronic Principles
Start date / 28/2/11
Deadline / 17/3/11
Assessor name / Paul Lewis
Assignment title / DC Networks
Context
The purpose of this assignment is to allow learner’s to develop skills in calculating current, voltage and resistance in simple DC networks. Following the calculation phase, learners will have the opportunity to confirm the calculated results with practical and simulated measurements.
Learners will be observed correctly setting up and using a multimeter to safely measure voltage, current and resistance.
You must show all of your calculations when submitting this assignment. Simplified and annotated circuit diagrams will also greatly enhance your presentation.
Task 1 Electrical and Electronic Principles P1
For the circuit shown below: Circuit 1

Choose 5 different value resistors from the attached table for R1 – R5
Choose a value of supply voltage from the table for V1
Calculate:
  1. The total circuit resistance Rt
  2. The total circuit current It
  3. The current flowing through R3
  4. The voltage dropped across R2
  5. The power dissipated by R1
Care should be taken by each student to ensure that the combination of components and supply voltage are unique for each assessment.
Task 2 Electrical and Electronic Principles
Construct the circuit shown above on breadboard
Use a multimeter to measure the total resistance of the circuit constructed for P1
Measure:
  1. The total resistance of the circuit (without it being connected to a power source)
  2. Connect the circuit to a DC voltage source, adjust the voltage to the value chosen for P1 above
  3. The total circuit current
  4. The current flowing through R3
  5. The voltage dropped across R2

Task 3 optional for P1 & P2 Electrical and Electronic Principles
Although this is not a compulsory task, it will provide valuable evidence towards both of the outcomes listed above and its good practice for some of the tasks you will complete later on in the unit.
  1. Use Multisim to simulate the circuit
  2. Use the virtual instruments to confirm the results of practical testing and calculation
  3. Once the circuit is completed with test instruments, carry out a screen dump and attach it to your completed assignment

Task 4 M1 Electrical and Electronic Principles
For the circuit shown below:
Circuit 2

  1. From the attached table choose different values for R1 – R3
  2. From the attached table choose different voltages for V1 –V2
  3. Use Kirchoff’s laws to determine the current flowing through R1, R2 and R3
  4. Determine the power dissipation in R1
  5. Use Multisim to confirm the results of your calculations and attach to the assignment as a screen dump

This brief has been verified as being fit for purpose
Assessor
Signature / Date
Internal verifier
Signature / Date

Table 1

Choose 5 different value resistors and a voltage value for circuit 1

Choose 3 different resistor values and 2 different voltage values for circuit 2

Resistor values / Voltage values
10 Ω / 3 volts
22 Ω / 5 volts
33 Ω / 6 volts
47 Ω / 9 volts
100 Ω / 10 volts
220 Ω / 12 volts
330 Ω / 15 volts
470 Ω / 24 volts
1k Ω

Circuit Measurements for circuit P1

Parameter / Calculated values / Measured values / Simulated values
Total circuit resistance
Total circuit current
Current flowing through R3
Voltage dropped across R2
Power dissipated in R1

Observation Questions

Question / Response
1)What is the tolerance of the resistors used in this circuit?
2)
3)How can you tell what tolerance value a resistor has?
4)Are the measured values and calculated values for the total resistance of the circuit within tolerance?
5)
6)What is the maximum power dissipation for the resistors used in this circuit?
7)Why is it important that you check the resistance of the multimeter probes before connecting the multimeter to a circuit?
8)How should a multimeter be set up to measure current?
9)How should a multimeter be set up to measure voltage?
10)How should a multimeter be set up to measure resistance?
11)Name two checks you should carry out on a multimeter prior to using it?
12)Why is it important that you check the condition of the multimeter and its probes before use?
13)How would you proceed to test a circuit if you did not know the value of the supply voltage (assume the supply voltage is below 380 volts)
14)How would you use a multimeter to ensure that an electrical circuit is isolated and safe to work on?

Finally remember you must show all of your working out, diagrams and sketches attached with this submission. Please check all have been completed before handing in.

Diploma Learner Observation Record

Qualification / Location of observation
Unit title and number / Date
Learner’s name / Observer name
Learner’s
signature / Observer signature
Description of activity undertaken
For this observation the learner:
  1. Safely constructed a DC network comprising of 5 resistors
  2. Connected the network to a DC source (5 volts)
  3. Correctly demonstrated the safe use of a multimeter
  4. Used a multimeter to measure voltage, current and resistance in accordance with the set tasks
  5. Was able to contrast and compare the readings taken by a multimeter with calculated and simulated results
Comments and feedback from the observation
This observation is evidence towards the following outcomes
Electrical and Electronic Principles
P2:
Use a multimeter to carry out circuit measurements in a DC network / Grade Pass/Refer