SHS3 Applied Technology · Semester 2 Week 14: Electronic Components and Circuits

Lesson notes

Learning Objectives

Indicator: 3.5.2.LI.2 - Apply the principle of operation of Timers in designing circuits

By the end of the lesson, learners can:

State the pin configuration and functions of the 555 timer IC in a mono-stable circuit configuration.
Explain how a 555 timer produces a timed output pulse using external resistor and capacitor values.
Design a mono-stable multi-vibrator circuit using a 555 timer IC to produce a specified time delay.
Simulate a mono-stable timer circuit using Multisim software and verify the calculated time delay.
Build and test a 555 timer mono-stable circuit on a breadboard, measuring the output pulse width with a multimeter or oscilloscope.

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Curriculum details

Strand: Electrical and Electronic Technology (Strand 5)
Sub-strand: Electronic Components and Circuits (5.2)
Content standard: 3.5.2.CS.1 - 3.5.2.CS.1 Demonstrate knowledge and understanding of electronic components and use them to design and construct electronic circuits. 3.5.2.LO.1 Demonstrate knowledge and understanding of electronic components and use them to design and construct electronic circuits.
Indicator: 3.5.2.LI.2 - Apply the principle of operation of Timers in designing circuits
Suggested placement: Semester 2, Week 14 (Week 34 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Source document note: The official curriculum document has a fault in this entry, so the curriculum text above is transcribed exactly as printed:

content standard text - p.189: prints the content-standard code as "2.5.2.CS.1"; filed under the section's own 3.5.2.CS.1
content standard text - p.189: prints the learning-outcome code as "2.4.2.LO.1"; filed under the section's own 3.5.2.LO.1
content standard text - p.189: the front page prints "Strand 4." for Electrical and Electronic Technology inside the YEAR THREE section, where Year 3's strand 4 is Wood Technology (printed pp.164 and 170); the Contents page (printed p.6) prints "STRAND 5. ELECTRICAL AND ELECTRONIC TECHNOLOGY" for Year 3 and Year 2 numbers the same strand 5, so the row is filed under strand 5
indicator text - p.189: prints the learning-indicator code as "2.5.2.LI.2"; filed under the section's own 3.5.2.LI.2
exemplars - p.189: prints the assessment code as "2.5.2.AS.2"; filed under the section's own 3.5.2.AS.2
Curriculum reference: NaCCA curriculum document, p. 189

Exemplars (from the NaCCA curriculum)

Focal Area: Designing with Integrated Circuit Principles of Operations of Integrated Circuits(Timers 555, 556 Designing circuits with Timers Pedagogy
Collaborative Learning: Work in pairs to; Explain how each IC can be connected in a circuit for a typical function e.g. timer,
Independent project work: Task learners individually to Design and construct multi-vibrators and encourage them to really do independent work as well as exhibiting a sense of responsibility when working with tools in the workshop (in terms theft).
Project based learning and collaboration: Engage learners in mixed gender groupings to: Design and simulate multi-vibrators (monostable, bi-stable and a stable) with 555 and 556 timer IC using Multisim NB: Ensure all learners participate in all varieties of practical activities and project work given and also when practical wiring is being carried out, girls and the physically challenged should not be left out. If possible, some of them should be made group leaders. Learners who may be physically challenged should be given enough time to complete the project work.

Assessment (3.5.2.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding; Level 3 Strategic reasoning.

Teaching and Learning Materials:
- Computers installed with multism software
- Electronic Components
- multimeters
- the use of the internet