-SQA-SCOTTISH QUALIFICATIONS AUTHORITY
HIGHER NATIONAL UNIT SPECIFICATION
GENERAL INFORMATION
-Unit number-
2461038
-Unit title-
DC NETWORKS
-Superclass category-
XJ
-Date of publication(month and year)
MAY 1998
-Originating centre for unit-
SQA
-----------------------------------------DESCRIPTIONGENERAL COMPETENCE FOR UNIT: Applying Kirchhoff’s Laws, reduction
techniques, network theorems and measurement techniques to do electrical
networks.
OUTCOMES:
1.
apply reduction and measurement techniques to evaluate a dc network;
2.
apply branch current analysis to solve a dc network;
3.
apply network theorems to solve dc networks.
CREDIT VALUE: 1 HN Credit.
ACCESS STATEMENT: Access to this unit is at the discretion of the centre.
However, it would be beneficial if the candidate had a basic understanding of d.c.
and a.c. circuit principles. This may be evidenced by possession of Higher Grade
Physics and/or NC module:
2160010 Electrical Fundamentals;
2160020 Circuit Elements;
2160030 Single Phase A.C.;
2160090 D.C. and A.C. Circuit Responses
or similar qualifications or experience.
-----------------------------------------
Unit No.2461038
Continuation
Additional copies of this unit can be obtained from:
The Committee and Administration Unit, SQA, Hanover House, 24 Douglas
Street, Glasgow G2 7NQ, (Tel: 0141-242 2168).
At the time of publication the cost is £1.50 per unit (minimum order £5.00).
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Unit No.2461038
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
STATEMENT OF STANDARDS
Unit number: 2461038
Unit title:
DC NETWORKS
Acceptable performance in this Unit will be the satisfactory achievement of the
standards set out in this part of the specification. All sections of the statement of
standards are mandatory and cannot be altered without reference to SQA.
OUTCOME
1.
APPLY REDUCTION AND MEASUREMENT TECHNIQUES TO
EVALUATE A DC NETWORK
PERFORMANCE CRITERIA
(a)
(b)
(c)
Ohm’s Law is verified by correct evaluation of experimental results.
A network of resistors is correctly reduced to its equivalent total
resistance.
Circuit parameters are correctly calculated for a simple D.C.
network.
RANGE STATEMENT
Resistive network: series; parallel.
Parameters: current; voltage; power; energy.
EVIDENCE REQUIREMENTS
Written evidence in the form of a report indicating test results to verify Ohm’s Law
and the reduction technique.
Graphical evidence is required to show that the candidate can verify OHm’s Law
by recording voltages and currents in a series d.c. circuit containing one voltage
source and two resistors.
Written evidence is also required to demonstrate that the candidate can verify the
reduction technique by calculations and recording voltages and currents in a
series – parallel d.c. circuit having one source.
Written evidence is also required to demonstrate that the candidate can calculate
power and energy in a d.c. circuit.
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Unit No.2461038
Continuation
OUTCOME
2.
APPLY BRANCH CURRENT ANALYSIS TO SOLVE A D.C.
NETWORK
PERFORMANCE CRITERIA
(a)
(b)
Branch currents in a two-mesh network with more than one source
are correctly determined using Kirchhoff’s laws.
Two-mesh networks with two sources are constructed and circuit
quantities are correctly metered, recorded and analysed.
RANGE STATEMENT
The range for this statement is fully expressed in the performance criteria.
EVIDENCE REQUIREMENTS
Written evidence is required to show that the candidate can calculate branch
currents in a two mesh, two source d.c. circuit by apply Kirchhoff’s Laws.
Written evidence in the form of a report is also required to demonstrate that the
candidate can verify Kirchhoff’s Laws from test results.
OUTCOME
3.
APPLY NETWORK THEOREMS TO SOLVE D.C. NETWORKS
PERFORMANCE CRITERIA
(a)
(b)
Network theorems are correctly applied to the calculation of
voltages and currents in a DC network.
Thevenis and Nortons theorems are correctly verified from test
results from a two mesh network.
RANGE STATEMENT
Network theorems:
transfer.
Thevenins; Nortons; superposition and maximum power
EVIDENCE REQUIREMENTS
Written evidence is required to show that the candidate can apply network
theorems to some d.c. networks.
Written evidence in the form of a report is also required to demonstrate that the
candidate can verify Thevenin’s and Norton’s theorems from test results
measured on the circuit used to verify Kirchhoff’s Laws in outcome 2. The reports
in outcomes 2 and 3 may be combined together as one exercise.
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Unit No.2461038
Continuation
MERIT STATEMENT: To gain a pass in this unit, a candidate must meet the
standards set out in the outcomes, performance criteria, range statements and
evidence requirements.
To achieve a merit in this unit, a candidate must demonstrate a superior or more
sophisticated level of performance. In this unit this might be demonstrated by the
use of more complex measurement techniques and calculations.
ASSESSMENT
In order to achieve this unit, candidates are required to present sufficient evidence
that they have met all the performance criteria for each outcome within the range
specified. Details of these requirements are given for each outcome. The
assessment instruments used should follow the general guidance offered by the
Scottish Qualifications Authority (SQA) assessment model and an integrative
approach to assessment is encouraged. (See references at the end of support
notes).
Accurate records should be made of the assessment instruments used showing
how evidence is generated for each outcome and giving marking schemes and/or
checklists, etc. Records of candidates’ achievements should be kept. These
records will be available for external verification.
SPECIAL NEEDS
Proposals to modify outcomes, range statements or agreed assessment
arrangements should be discussed in the first place with the external verifier.
 Copyright SQA 1998
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
5
Unit No.2461038
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
SUPPORT NOTES
Unit number: 2461038
Unit title:
DC NETWORKS
SUPPORT NOTES: This part of the unit specification is offered as guidance.
None of the sections of the support notes is mandatory.
NOTIONAL DESIGN LENGTH: SQA allocates a notional design length to a unit
on the basis of time estimated for achievement of the stated standards by a
candidate whose starting point is as described in the access statement. The
notional design length for this unit is 40 hours. The use of notional design length
for programme design and timetabling is advisory only.
PURPOSE The purpose of this unit is to provide a foundation in the theories and
analysis techniques required in the application of D.C. Networks. The unit is
intended to provide candidate with both theoretical and practical expertise and
should be taught and assessed in that manner.
CONTENT/CONTEXT Corresponding to outcomes:
Outcome 1
Current, voltage, power, energy. Arrow and double subscript notations for voltage
and current. Resistance. Ohm’s Law. Kirchhoff’s Laws. Circuit reduction
techniques. Voltage and current (two resistors only) division rules.
Outcome 2
Voltage and current sources, source transformations. Kirchhoff’s Laws applied to
a d.c. circuit.
Outcome 3
Thevenin’s, Norton’s superposition and maximum power transfer theorems.
APPROACHES TO GENERATING EVIDENCE The unit should be taught in a
classroom environment where access to a laboratory and computers with suitable
simulation packages are available.
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Unit No.2461038
Continuation
ASSESSMENT PROCEDURES Centres may use Instruments of Assessment
which are considered by tutors/trainers to be most appropriate.
Outcome 1
Report on the practical or computer simulation tests.
Outcome 2
Structured questions and a report on the practical or computer
simulation tests.
Outcome 3
Structured questions and a report on the practical or computer
simulation tests.
PROGRESSION
Achievement of this unit would provide a sound basis for
access to unit 2461048 AC Networks.
REFERENCES
1.
2.
3.
4.
Guide to unit writing, SQA, 1993 (Code: A018).
Guide to assessment, SQA, 1993 (Code: B005).
Guide to certification, SQA, 1996 (Code: F025).
Notes for unit writers, SQA, 1995 (Code: A041).
For details of other SQA publications, please contact staff in the Sales and
Despatch section (Tel: 0141-242 2168) who can supply you with a copy of the
publication list (Code: X037).
 Copyright SQA 1998
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
7