Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 2nd Term
Week: 10
Age: 15 years
Duration: 45 minutes
Subject: Basic Electronics
Curriculum Theme: Basic Electronics
Previous Lesson: Circuit Arrangement: Series, Parallel and Series-Parallel Wiring.
Topic: SIMPLE CALCULATION ON CIRCUIT ARRANGEMENT.
Subject Matter: Calculating resistance in series arrangement, calculating resistance in parallel arrangement, calculating resistance in series parallel arrangement, solving simple circuit arrangement problems.

Specific Objectives

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

Cognitive Domain:

Define series, parallel, and series-parallel circuit arrangements.
State the formulas for calculating total resistance in series and parallel circuits.
Differentiate between series and parallel circuit arrangements.
Solve simple problems involving total resistance in series, parallel, and series-parallel circuits.

Affective Domain:

Appreciate the importance of understanding circuit calculations in electronics.
Show interest in solving problems related to circuit arrangements.

Psychomotor Domain:

Draw simple diagrams of series, parallel, and series-parallel circuits.
Apply the correct formulas to calculate total resistance in given circuit arrangements.

Collaborate with peers to solve circuit problems.

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 Electronics for Senior Secondary Schools by a relevant author.

Instructional Materials

The teacher will teach this lesson with the aid of:

Charts showing circuit arrangements (series, parallel, series-parallel).
Sample circuit diagrams drawn on the whiteboard.
Calculators.

Rationale for the Lesson

This lesson helps pupils understand how to calculate total resistance in different electrical circuits. This knowledge is important for designing, troubleshooting, and understanding the behavior of electronic devices and systems they encounter daily.

Prerequisite/Previous Knowledge

Pupils are assumed to have prior knowledge of basic electrical concepts such as current, voltage, resistance, and Ohm’s Law.

Lesson Content/Board Summary

SIMPLE CALCULATION ON CIRCUIT ARRANGEMENT

Resistance in Series Arrangement

In a series circuit, components are connected end-to-end, forming a single path for current flow. The total resistance in a series circuit is the sum of individual resistances.

The formula for total resistance (R_T) in a series circuit is:

R_T = R₁ + R₂ + R₃ + … + R_n

Resistance in Parallel Arrangement

In a parallel circuit, components are connected across the same two points, providing multiple paths for current flow. The reciprocal of the total resistance in a parallel circuit is the sum of the reciprocals of individual resistances.

The formula for total resistance (R_T) in a parallel circuit is:

1/R_T = 1/R₁ + 1/R₂ + 1/R₃ + … + 1/R_n

For two resistors in parallel, a simpler formula can be used:

R_T = (R₁ × R₂) / (R₁ + R₂)

Resistance in Series-Parallel (Combined) Arrangement

A series-parallel circuit combines both series and parallel connections. To calculate total resistance, simplify the parallel sections first, then treat the simplified sections as series components.

Steps to calculate total resistance in a series-parallel circuit:

Identify and simplify all parallel sections first using the parallel resistance formula.
Redraw the circuit with the simplified parallel sections replaced by their equivalent resistances.
Calculate the total resistance of the resulting series circuit using the series resistance formula.

Solving Simple Circuit Arrangement Problems

When solving circuit problems, it is important to:

Draw the circuit diagram clearly if not provided.
Identify whether sections are in series or parallel.
Apply the correct formula for each section.
Perform calculations carefully, step-by-step.
State the final answer with appropriate units (Ohms, Ω).

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 types of electrical circuits. The teacher then introduces the topic by asking pupils how they think electricians determine the overall resistance of a complex circuit.
Pupils’ Activity: Pupils respond to questions and listen attentively to the introduction.
Learning Point: Pupils recall previous knowledge and are prepared for the new topic.

Step 2: Presentation of Resistance in Series Arrangement

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains what a series circuit is, draws a simple series circuit on the board, and presents the formula for calculating total resistance. The teacher works through a sample calculation.
Pupils’ Activity: Pupils observe the diagrams, copy notes, and ask questions for clarification.
Learning Point: Pupils understand how to calculate total resistance in series circuits.

Step 3: Presentation of Resistance in Parallel Arrangement

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains what a parallel circuit is, draws a simple parallel circuit on the board, and presents the formula for calculating total resistance. The teacher works through a sample calculation.
Pupils’ Activity: Pupils observe the diagrams, copy notes, and participate in discussions.
Learning Point: Pupils understand how to calculate total resistance in parallel circuits.

Step 4: Presentation of Resistance in Series-Parallel Arrangement

Time: 7 minutes
Teaching Skill: Explanation/Problem Solving
Teacher’s Activity: The teacher explains series-parallel circuits and outlines the steps for calculating total resistance in such arrangements. The teacher demonstrates by solving a simple series-parallel problem on the board.
Pupils’ Activity: Pupils pay attention to the steps and ask questions to clarify the process.
Learning Point: Pupils learn the method for simplifying and calculating total resistance in combined circuits.

Step 5: Class Activity/Practice

Time: 5 minutes
Teaching Skill: Application/Guided Practice
Teacher’s Activity: The teacher gives pupils a simple circuit problem (either series, parallel, or a basic series-parallel) to solve in their notebooks. The teacher walks around to provide guidance.
Pupils’ Activity: Pupils attempt to solve the given problem individually or in pairs.
Learning Point: Pupils apply the learned formulas to solve practical problems.

Step 6: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

Define a series circuit and state the formula for its total resistance.
How does a parallel circuit differ from a series circuit?
Calculate the total resistance of two resistors, 10Ω and 15Ω, connected in series.
Calculate the total resistance of two resistors, 10Ω and 15Ω, connected in parallel.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 7: Conclusion

Time: 3 minutes
Teaching Skill: Summarization/Consolidation
Teacher’s Activity: The teacher summarizes the key points of the lesson, emphasizing the difference in calculating resistance for series, parallel, and series-parallel circuits. The teacher gives homework involving more complex circuit problems.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: The lesson is concluded, and learning is reinforced.

Lesson Keywords

Series Circuit – An electrical circuit in which components are connected one after another, forming a single path for current.
Parallel Circuit – An electrical circuit in which components are connected across the same two points, providing multiple paths for current.
Series-Parallel Circuit – A circuit arrangement that combines both series and parallel connections.
Resistance (R) – A measure of the opposition to current flow in an electrical circuit, measured in Ohms (Ω).
Total Resistance (R_T) – The equivalent resistance of a combination of resistors in a circuit.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide more complex series-parallel problems. For those who need more support, the teacher can offer simpler problems or pair them with faster learners for peer tutoring. Visual aids like coloured diagrams will assist visual learners.

Note for teachers using this lesson plan

Ensure that pupils have a good understanding of basic arithmetic operations, especially fractions, before tackling parallel resistance calculations. Emphasize drawing circuit diagrams clearly as a first step in problem-solving. Encourage the use of calculators and provide sufficient practice problems.