Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 6
Age: 15 years
Duration: 45 minutes
Subject: Basic Electronics
Curriculum Theme: Basic Electronics
Previous Lesson: Electric Current: Differences Between DC and AC.
Topic: ELECTRIC CURRENT Sources of direct and alternating current.
Subject Matter: sources of direct current, sources of alternating current, identifying DC sources, identifying AC sources, examples of common DC and AC sources

Specific Objectives

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

Cognitive Domain:

Define direct current (DC) and alternating current (AC).
List at least three sources of direct current.
List at least two sources of alternating current.
Identify common examples of DC and AC sources.

Affective Domain:

Appreciate the importance of knowing different types of electric current and their sources.
Show interest in learning more about electronic components.

Psychomotor Domain:

Draw simple representations of DC and AC waveforms.
Distinguish between physical examples of DC and AC sources.

Participate actively in class discussions on current sources.
Collaborate with peers to identify various current sources.

Reference Materials

The following resources were used in planning this lesson:

Senior Secondary Education Curriculum for Basic Electronics.
State Unified Scheme of Work for Senior Secondary Schools.
Basic Electronics for Senior Secondary Schools by A.O. Okoro.
Charts showing AC sources.

Instructional Materials

The teacher will teach this lesson with the aid of:

Dry cells
Batteries
Charts showing AC sources (e.g., power outlets, generators)
Blackboard/Whiteboard and markers/chalk

Rationale for the Lesson

This lesson helps pupils understand the two main types of electric current that power our devices and homes. Knowing the sources of direct and alternating current is important for safe and effective use of electrical appliances in their daily lives.

Prerequisite/Previous Knowledge

Pupils should have a basic understanding of electric current and simple circuits from their Junior Secondary education.

Lesson Content/Board Summary

ELECTRIC CURRENT: Sources of Direct and Alternating Current

1. Definition of Direct Current (DC)

Direct Current (DC) is an electric current that flows in only one direction in a circuit. Its voltage remains constant over time.

2. Sources of Direct Current (DC)

The following are common sources of direct current:

Dry cells (e.g., AA, AAA batteries)
Batteries (e.g., car batteries, phone batteries)
DC generators
Solar cells/panels
Rectified AC power supplies

3. Definition of Alternating Current (AC)

Alternating Current (AC) is an electric current that periodically reverses direction. Its voltage level also reverses periodically.

4. Sources of Alternating Current (AC)

The following are common sources of alternating current:

AC generators (alternators)
Power stations (national grid)
Inverters (converting DC to AC)
Home wall sockets/outlets

5. Identifying DC and AC Sources

It is important to identify whether a device uses DC or AC for proper usage and safety. DC sources often have positive (+) and negative (-) terminals clearly marked, while AC sources are typically household wall outlets or power lines.

Examples of common DC sources include:

Torchlight batteries
Laptop batteries
Car batteries
Solar panel outputs

Examples of common AC sources include:

Wall sockets in homes and offices
Large power generators
Inverters used for home backup power

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 reviews the previous lesson on basic electric current. The teacher then asks pupils to mention some electrical appliances they use daily and how they get power.
Pupils’ Activity: Pupils respond to the greetings and questions, mentioning appliances like phones, fans, and light bulbs.
Learning Point: Pupils recall previous knowledge and are introduced to the lesson topic.

Step 2: Presentation of Direct Current (DC)

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher defines Direct Current (DC) and explains its characteristics. The teacher then presents examples like dry cells and batteries, demonstrating how they provide power and lists other sources of DC.
Pupils’ Activity: Pupils listen attentively, observe the dry cells and batteries, and take notes.
Learning Point: Pupils understand the definition and sources of DC.

Step 3: Presentation of Alternating Current (AC)

Time: 10 minutes
Teaching Skill: Explanation/Visual Aid
Teacher’s Activity: The teacher defines Alternating Current (AC) and explains its characteristics. Using charts, the teacher shows examples of AC sources like wall sockets and power generators, and lists other sources of AC.
Pupils’ Activity: Pupils listen, observe the charts, and take notes.
Learning Point: Pupils understand the definition and sources of AC.

Step 4: Identification of DC and AC Sources

Time: 5 minutes
Teaching Skill: Guided Discovery
Teacher’s Activity: The teacher guides pupils to identify common electrical sources around them (e.g., phone chargers, power outlets) and asks them to classify them as DC or AC sources based on the definitions and examples discussed.
Pupils’ Activity: Pupils participate by identifying and classifying sources, asking questions for clarification.
Learning Point: Pupils can differentiate between common DC and AC sources.

Step 5: Discussion of Differences

Time: 5 minutes
Teaching Skill: Facilitation
Teacher’s Activity: The teacher facilitates a brief discussion on the key differences between DC and AC, emphasizing their flow direction and voltage stability. The teacher clarifies any misconceptions.
Pupils’ Activity: Pupils contribute to the discussion, comparing and contrasting DC and AC based on the information learned.
Learning Point: Pupils consolidate their understanding of the distinct characteristics of DC and AC.

Step 6: Class Activity/Pupil Engagement

Time: 5 minutes
Teaching Skill: Engagement/Application
Teacher’s Activity: The teacher divides the class into small groups and gives each group a task to list five DC sources and five AC sources they encounter in their daily lives. The teacher monitors and provides assistance.
Pupils’ Activity: Pupils work in groups, brainstorm, and list the required sources.
Learning Point: Pupils apply their knowledge to real-life examples and work collaboratively.

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 Direct Current (DC).
Mention three sources of Direct Current.
Define Alternating Current (AC).
List two common sources of Alternating Current.
Give an example of a device that uses a DC source and one that uses an AC source.

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 definitions and sources of DC and AC. The teacher then gives an assignment: “Research and write down one advantage and one disadvantage of using AC over DC for power transmission.”
Pupils’ Activity: Pupils listen to the summary and copy the assignment.
Learning Point: Pupils reinforce their learning and are given tasks for further study.

Lesson Keywords

Direct Current (DC) – Electric current that flows in only one direction.
Alternating Current (AC) – Electric current that periodically reverses direction.
Battery – A device that stores chemical energy and converts it into electrical energy (DC).
Generator – A machine that converts mechanical energy into electrical energy (can be AC or DC).
Solar Cell – A device that converts light energy into electrical energy (DC).
Wall Socket – A point in a wiring system where an electrical appliance can be connected (AC).

Differentiation

For pupils who grasp concepts quickly, the teacher can challenge them to explain why AC is preferred for long-distance power transmission. For pupils needing more support, the teacher can provide simplified diagrams and allow them to work with a partner to identify sources.

Note for teachers using this lesson plan

Ensure that actual dry cells and batteries are available for demonstration. The charts for AC sources should be clear and visible to all pupils. Encourage active participation and real-world examples to make the lesson relatable and engaging.