Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 3rd Term
Week: 8
Age: 15 years
Duration: 45 minutes
Subject: Basic Electricity
Curriculum Theme: Basic Electricity
Previous Lesson: Converters: Meaning and Types.
Topic: INVERTERS
Subject Matter: Definition of inverter, functions of inverter, differences between inverter and converter, basic demonstration of inverter use.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Define an inverter.
State at least three functions of an inverter.
Differentiate between an inverter and a converter.

Affective Domain:

Appreciate the importance of inverters in daily life.
Show interest in the working principles of electrical power conversion devices.

Psychomotor Domain:

Identify the main components of an inverter unit.
Observe a basic demonstration of how an inverter works.

Participate actively in discussions about inverters and converters.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Technology.
State Unified Scheme of Work for Senior Secondary Schools.
Basic Electricity for Senior Secondary Schools by A. O. Olarinoye.

Instructional Materials

The teacher will teach this lesson with the aid of:

An inverter unit.
A 12V DC battery.
A load device (e.g., a light bulb or fan).
Charts showing inverter output waveforms.

Rationale for the Lesson

This lesson helps pupils understand how DC power from batteries can be converted to AC power for running household appliances. Knowing about inverters is important for understanding backup power systems commonly used in homes and businesses.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of direct current (DC) and alternating current (AC), as well as an understanding of simple electrical circuits.

Lesson Content/Board Summary

INVERTERS

Definition of Inverter

An inverter is an electronic device that converts direct current (DC) from a source like a battery into alternating current (AC) suitable for powering standard household appliances.

Functions of an Inverter

The following are functions of an inverter:

It converts DC power to AC power.
It provides backup power during power outages when connected to a battery.
It allows the use of DC power sources (like solar panels or batteries) to operate AC loads.
It can regulate the output voltage and frequency for sensitive electronic devices.

Differences between Inverter and Converter

Inverters and converters both deal with power conversion, but they perform opposite functions:

Inverter: Converts DC power to AC power.
Converter: Converts AC power to DC power (e.g., a phone charger).
Inverter Use: Powers AC appliances from a battery.
Converter Use: Charges batteries or powers DC devices from an AC mains supply.

Basic Demonstration of Inverter Use

To demonstrate an inverter, a DC battery is connected to the input terminals of the inverter. An AC load, such as a light bulb or fan, is then connected to the output terminals of the inverter. When the inverter is switched on, it draws DC power from the battery and converts it into AC power, causing the AC load to operate.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them about common power backup solutions they know or use at home (e.g., generators, battery backup). The teacher then leads the discussion towards the concept of devices that convert battery power to usable household electricity.
Pupils’ Activity: Pupils respond to the questions and share their experiences.
Learning Point: Pupils are engaged and their prior knowledge is activated, preparing them for the topic of inverters.

Step 2: Presentation of Topic

Time: 2 minutes
Teaching Skill: Introduction
Teacher’s Activity: The teacher writes the topic “INVERTERS” on the board and states the specific objectives for the lesson.
Pupils’ Activity: Pupils listen attentively and copy the topic into their notebooks.
Learning Point: Pupils know what they are expected to learn during the lesson.

Step 3: Definition of Inverter

Time: 8 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines an inverter as an electronic device that converts DC power into AC power. The teacher explains the terms DC and AC briefly and gives examples of DC sources (batteries) and AC loads (household appliances).
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the definition of an inverter and its primary function.

Step 4: Functions of an Inverter

Time: 8 minutes
Teaching Skill: Elucidation/Listing
Teacher’s Activity: The teacher explains the various functions of an inverter, such as providing backup power and allowing DC sources to power AC loads. The teacher writes these functions on the board.
Pupils’ Activity: Pupils listen, contribute to the discussion, and copy the functions from the board.
Learning Point: Pupils can state the uses and importance of inverters.

Step 5: Differences between Inverter and Converter

Time: 7 minutes
Teaching Skill: Comparison/Differentiation
Teacher’s Activity: The teacher explains that while both devices convert power, they do so in opposite directions. The teacher outlines the key differences between an inverter (DC to AC) and a converter (AC to DC), providing examples of each.
Pupils’ Activity: Pupils listen, compare the two devices, and note down the differences.
Learning Point: Pupils can distinguish between an inverter and a converter based on their functions.

Step 6: Basic Demonstration of Inverter Use

Time: 5 minutes
Teaching Skill: Demonstration
Teacher’s Activity: The teacher connects the inverter unit to a battery and then connects a load (e.g., a light bulb) to the inverter’s output. The teacher switches on the inverter to show how it powers the load, explaining each step.
Pupils’ Activity: Pupils observe the demonstration carefully and ask questions about the connections and operation.
Learning Point: Pupils gain practical insight into how an inverter works.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define an inverter.
Mention two functions of an inverter.
State one key difference between an inverter and a converter.
What type of current does an inverter convert from and to?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the definition, functions, and differences between inverters and converters. The teacher then assigns homework.
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: The lesson is reinforced, and pupils are given an opportunity to practice.

Lesson Keywords

Inverter – An electronic device that converts DC power to AC power.
Converter – An electronic device that converts AC power to DC power.
DC (Direct Current) – Electric current that flows in only one direction.
AC (Alternating Current) – Electric current that periodically reverses direction.
Battery – A device that stores chemical energy and converts it into electrical energy (DC).
Load – An electrical component or portion of a circuit that consumes electric power.

Differentiation

For pupils who grasp concepts quickly, they can be challenged to research different types of inverters (e.g., pure sine wave, modified sine wave) and their applications. For pupils who need more support, visual aids such as diagrams of power flow and repeated demonstrations will be used. Group activities will encourage peer learning and collaboration among diverse learners.

Note for teachers using this lesson plan

Ensure that the inverter unit and battery are in good working condition before the demonstration. Emphasize safety precautions when handling electrical devices. Encourage pupils to ask questions and relate the concepts to their everyday experiences with electricity.