-SQA-SCOTTISH QUALIFICATIONS AUTHORITY
HIGHER NATIONAL UNIT SPECIFICATION
GENERAL INFORMATION
-Unit Number-
2451557
-Superclass-
XL
-Title-
OPERATIONAL AMPLIFIERS
-----------------------------------------DESCRIPTIONGENERAL COMPETENCE FOR UNIT: Understanding the operating principles
of operational amplifiers and designing and constructing operational amplifier
circuits.
OUTCOMES
1.
explain the characteristics of ideal and practical operational amplifiers;
2.
design, construct and test operational amplifier circuits;
3.
specify operational amplifier frequency dependent characteristics.
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 prior knowledge of basic
analogue device operation and use. This may be evidenced by possession of
HN unit:
2451547 Analogue Electronic Devices
or similar qualifications or experience.
----------------------------------------For further information contact: Committee and Administration Unit, SQA,
Hanover House, 24 Douglas Street, Glasgow G2 7NQ.
Additional copies of this unit may be purchased from SQA (Sales and Despatch
section). At the time of publication, the cost is £1.50 (minimum order £5.00).
Unit No. 2451557
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
STATEMENT OF STANDARDS
UNIT NUMBER:
2451557
UNIT TITLE:
OPERATIONAL AMPLIFIERS
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.
EXPLAIN THE CHARACTERISTICS OF IDEAL AND PRACTICAL
OPERATIONAL AMPLIFIERS
PERFORMANCE CRITERIA
(a)
(b)
The characteristics of an ideal operational amplifier are correctly
stated.
The differences between the characteristics of an ideal
operational amplifier and a practical operational amplifier are
correctly explained with the aid of manufacturers’ data sheets.
RANGE STATEMENT
Characteristics: gain/bandwidth; input impedance; output impedance; commonmode rejection ratio, slew-rate; offset voltage; temperature stability.
EVIDENCE REQUIREMENTS
Written and graphical evidence that the candidate can state the characteristics of
an ideal operational amplifier given in the range statement and explain the
differences found in a practical operational amplifier.
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Unit No. 2451557
Continuation
OUTCOME
2.
DESIGN, CONSTRUCT AND TEST OPERATIONAL AMPLIFIER
CIRCUITS
PERFORMANCE CRITERIA
(a)
(b)
(c)
The expression for amplifier closed-loop gain is correctly derived.
Resistor values are correctly calculated for a specified amplifier
configuration and gain.
Circuits are suitably constructed and tested for a specified
application.
RANGE STATEMENT
Circuits: inverting amplifier; non-inverting amplifier; summing amplifier; difference
amplifier; voltage follower; precision rectifier.
EVIDENCE REQUIREMENTS
Written and performance evidence is required to show that the candidate can
design, construct and test operational amplifier circuits covering the full range
statement as defined for performance criteria (a) - (c).
OUTCOME
3.
SPECIFY
OPERATIONAL
AMPLIFIER
DEPENDENT CHARACTERISTICS
FREQUENCY
PERFORMANCE CRITERIA
(a)
(b)
(c)
The frequency dependence of the amplitude and phase response
of an amplifier is correctly described.
Amplifier equivalent circuits containing frequency dependent
components are correctly drawn and described.
Amplitude and phase frequency response Bode diagrams are
correctly drawn from experimental results.
RANGE STATEMENT
The range for this outcome is fully expressed in the performance criteria.
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Unit No. 2451557
Continuation
EVIDENCE REQUIREMENTS
Written and performance evidence is required to show that the candidate can
specify amplifier frequency dependent characteristics as defined for performance
criteria (a) - (c).
MERIT 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. This may be demonstrated by:
(i)
(ii)
aptitude in the construction and testing of the practical circuits;
the application of the theory to correctly solve unfamiliar problems.
-----------------------------------------
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 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 1997
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.
4
Unit No. 2451557
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
SUPPORT NOTES
UNIT NUMBER:
2451557
UNIT TITLE:
OPERATIONAL AMPLIFIERS
SUPPORT NOTES: This part of the unit specification is offered as guidance.
None of the sections of the support notes are 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 principles
involved in the design and construction of circuits using operational amplifiers.
CONTENT/CONTEXT Corresponding to outcomes:
Outcome 1
Amplifier equivalent circuit: input resistance, voltage source, output resistance.
Outcome 2
Amplifiers:
derivation of circuit gain for inverting and non-inverting
configurations. Calculation of component values for specified gain.
Construction and verification of operation of op-amp circuits: summing amplifier,
difference amplifier, voltage follower, precision rectifier.
Outcome 3
Amplitude and phase responses; Bode diagrams; equivalent circuits with
frequency dependent components, i.e. series and parallel capacitors to give low
and high frequency roll-off.
APPROACHES TO GENERATING EVIDENCE
The use of written tests to
enable the candidate to demonstrate competence in the analysis of circuits
coupled with appropriate build and test laboratory exercises are appropriate
assessment methods.
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Unit No. 2451557
Continuation
ASSESSMENT PROCEDURES Centres may use Instruments of Assessment
which are considered by tutors/trainers to be most appropriate.
Outcome 1 could be assessed by a written test to show that the candidate can
state the ideal characteristics of an operations amplifier and give typical values
for a practical amplifier. The data sheets to be used for this outcome could be
the data sheets for the operational amplifiers used in outcome 2 and 3”.
Outcome 2 could be assessed by a written test to show that the candidate can
derive the expressions for the closed-loop gain of each amplifier configuration
(inverting and non-inverting) and calculate resistor values for a specified gain.
Practical exercises could be used to show that the candidate can construct and
demonstrate a circuit for each of the specified circuits.
Outcome 3 could be assessed by a written report to show that the candidate can
obtain amplitude and phase measurements over a range of frequencies from a
practical circuit, plot Bode diagrams from these results and describe, with
reference to an equivalent circuit, how these frequency effects are produced.
PROGRESSION
Candidates should normally have passed unit 2451547
Analogue Electronic Devices.
This unit should be delivered in the latter stages of an HND programme.
REFERENCES
1.
2.
3.
4.
Guide to unit writing.
For a fuller discussion on assessment issues, please refer to SQA’s
Guide to Assessment.
Information for centres on SQA’s operating procedures is contained in
SQA’s Guide to Procedures.
For details of other SQA publications, please consult SQA’s publications
list.
 Copyright SQA 1997
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.
6