Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: 2nd Term
Week: 9
Age: 15 years
Duration: 45 minutes
Subject: GSM Maintenance And Repairs
Curriculum Theme: Trade
Previous Lesson: Power Supply And Amplifiers: Construction Features And Uses Of Power Supply.
Topic: The power supply and amplifiers
Subject Matter: Meaning of amplifier, Types of amplifier, Uses of amplifier

Specific Objectives

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

Cognitive Domain:

Define an amplifier.
Identify different types of amplifiers.
State at least three uses of amplifiers.

Affective Domain:

Appreciate the importance of amplifiers in various electronic devices.
Show interest in learning how amplifiers function.

Psychomotor Domain:

Recognise an amplifier board among other electronic components.

Share ideas about where amplifiers are used in daily life.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Technology (Trade & Entrepreneurship).
State Unified Scheme of Work for Senior Secondary Schools.
GSM Maintenance and Repairs for Senior Secondary Schools by a relevant author.

Instructional Materials

The teacher will teach this lesson with the aid of:

Audio amplifier board
Speaker
Signal generator
Power adapter
Charts showing different types of amplifiers

Rationale for the Lesson

This lesson helps pupils understand how electronic signals are made stronger in devices they use every day, like mobile phones and radios. It enables them to grasp a fundamental concept in electronics and GSM maintenance, which is important for troubleshooting and repair.

Prerequisite/Previous Knowledge

Pupils are expected to have basic knowledge of electricity, electronic components like resistors and capacitors, and how sound is produced.

Lesson Content/Board Summary

The Power Supply and Amplifiers

Meaning of Amplifier

An amplifier is an electronic device or circuit that increases the power, current, or voltage of a signal. It takes a weak input signal and produces a stronger output signal, making it more useful for various applications.

Types of Amplifier

Amplifiers can be classified based on their application or the type of signal they amplify. The following are common types of amplifiers:

Audio Amplifiers: Used to amplify sound signals, making them audible through speakers.
Radio Frequency (RF) Amplifiers: Used in radio and communication systems to amplify high-frequency signals.
Power Amplifiers: Designed to increase the power of a signal, often used as the final stage in audio systems to drive speakers.
Voltage Amplifiers: Primarily designed to increase the voltage of a signal.
Current Amplifiers: Designed to increase the current of a signal.

Uses of Amplifier

Amplifiers are essential components in many electronic devices. The following are some uses of amplifiers:

In radios and televisions to boost broadcast signals.
In public address systems to increase the volume of voices or music.
In mobile phones for both transmitting and receiving audio and radio signals.
In hearing aids to amplify sound for people with hearing impairments.
In medical equipment, such as ECG machines, to amplify tiny biological signals.
In home theatre systems and car stereos for audio amplification.
In communication systems like satellite dishes and radar.

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 to mention devices that produce sound and those that make sound louder. The teacher relates their answers to the concept of amplification.
Pupils’ Activity: Pupils respond by mentioning devices like radios, phones, and public address systems, and discuss how some make sounds louder.
Learning Point: Pupils are introduced to the lesson topic and its relevance to everyday technology.

Step 2: Meaning of Amplifier

Time: 10 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines an amplifier, explaining its basic function of increasing signal strength. The teacher writes the definition on the board.
Pupils’ Activity: Pupils listen attentively, ask questions for clarification, and copy the definition into their notebooks.
Learning Point: Pupils understand what an amplifier is and its primary role.

Step 3: Types of Amplifier

Time: 10 minutes
Teaching Skill: Classification/Illustration
Teacher’s Activity: The teacher explains different types of amplifiers (e.g., audio, RF, power, voltage, current amplifiers) with simple examples for each. The teacher uses charts to illustrate.
Pupils’ Activity: Pupils observe the charts, listen to the explanations, and identify the different types of amplifiers.
Learning Point: Pupils can differentiate between various types of amplifiers based on their function.

Step 4: Uses of Amplifier

Time: 10 minutes
Teaching Skill: Application/Demonstration
Teacher’s Activity: The teacher discusses various applications of amplifiers in technology and daily life. The teacher may demonstrate with the audio amplifier board, speaker, and signal generator if practical, showing how a low signal is boosted to produce audible sound. The teacher lists the uses on the board.
Pupils’ Activity: Pupils state common uses of amplifiers and observe the demonstration, noting down the applications.
Learning Point: Pupils understand the practical importance and widespread use of amplifiers.

Step 5: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define an amplifier.
Mention two types of amplifiers.
State three uses of amplifiers.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 6: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, highlighting the importance of amplifiers in electronics. The teacher gives an assignment: “Research and list other electronic devices that use amplifiers.”
Pupils’ Activity: Pupils listen to the summary and copy the assignment.
Learning Point: Pupils consolidate their understanding and are encouraged to research further.

Lesson Keywords

Amplifier – An electronic device that increases the power, current, or voltage of a signal.
Signal – An electrical quantity (voltage or current) that varies over time and carries information.
Gain – The ratio of the output signal power or amplitude to the input signal power or amplitude, indicating how much an amplifier boosts a signal.
Audio – Relating to sound or its reproduction.
RF (Radio Frequency) – Electromagnetic waves in the frequency range from about 3 kilohertz to 300 gigahertz.

Differentiation

For pupils who grasp concepts quickly, the teacher can challenge them to research different classes of amplifiers (e.g., Class A, B, AB). For those who need more support, the teacher will provide simplified diagrams and additional verbal explanations, focusing on the core definition and a few key examples of uses.

Note for teachers using this lesson plan

Ensure that the demonstration materials (audio amplifier board, speaker, signal generator) are functional before the lesson. Encourage pupils to ask questions and relate the concepts to devices they are familiar with. Emphasise safety when handling electronic components and power sources.