Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: 3rd Term
Week: 10
Age: 15 years
Duration: 45 minutes
Subject: Radio, Tv & Electronics
Curriculum Theme: Trade
Previous Lesson: Soldering And Desoldering In Electronic Circuits: Types Of Flux.
Topic: ELECTRONIC MEASURING INSTRUMENTS
Subject Matter: Uses of multimeter, Measuring current, Measuring voltage, Measuring resistance, Safety precautions

Specific Objectives

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

Cognitive Domain:

Define a multimeter.
State at least three uses of a multimeter.
Describe the steps for measuring current, voltage, and resistance using a multimeter.
List at least four safety precautions when using a multimeter.

Affective Domain:

Appreciate the importance of a multimeter in electronic work.
Show caution and responsibility when handling electronic measuring instruments.

Psychomotor Domain:

Set a multimeter to the correct range for measuring current, voltage, or resistance.
Demonstrate the proper connection of a multimeter to a circuit for basic measurements.

Follow teacher’s instructions regarding the safe use of measuring instruments.
Engage in discussions about proper measurement techniques.

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:

Digital multimeter
Test leads
A simple circuit board with components (resistor, battery, LED)
Chalkboard/Whiteboard
Chalk/Markers

Rationale for the Lesson

This lesson helps pupils understand how to use a multimeter, which is a fundamental tool in electronics. Knowing how to measure electrical quantities and observe safety precautions is important for practical work and for preventing damage to equipment or injury.

Prerequisite/Previous Knowledge

Pupils are assumed to have some basic knowledge of electricity, circuits, and simple electrical quantities like voltage, current, and resistance from previous lessons.

Lesson Content/Board Summary

ELECTRONIC MEASURING INSTRUMENTS

Multimeter

A multimeter is an electronic measuring instrument that combines several measurement functions in one unit. It is used to measure voltage (volts), current (amperes), and resistance (ohms).

Uses of a Multimeter

The following are common uses of a multimeter:

Measuring DC and AC voltage.
Measuring DC and AC current.
Measuring resistance of components.
Checking for continuity in wires or circuits.
Testing diodes and transistors.

Measuring Current with a Multimeter

To measure current in a circuit:

Turn off power to the circuit.
Select the appropriate current range (A for amperes) on the multimeter, ensuring it is set for DC or AC as needed.
Connect the red test lead to the “mA” or “A” jack and the black test lead to the “COM” jack.
Break the circuit at the point where current is to be measured and connect the multimeter in series with the circuit.
Turn on the power and read the value.

Measuring Voltage with a Multimeter

To measure voltage across a component or power source:

Select the appropriate voltage range (V for volts) on the multimeter, ensuring it is set for DC or AC as needed.
Connect the red test lead to the “VΩmA” jack and the black test lead to the “COM” jack.
Connect the test leads in parallel across the component or power source to be measured.
Read the voltage value displayed.

Measuring Resistance with a Multimeter

To measure the resistance of a component (e.g., a resistor):

Ensure the component is removed from any powered circuit.
Select the resistance range (Ω for ohms) on the multimeter.
Connect the red test lead to the “VΩmA” jack and the black test lead to the “COM” jack.
Touch the test leads across the terminals of the component.
Read the resistance value displayed.

Safety Precautions When Using a Multimeter

The following are important safety precautions:

Always select the correct function (voltage, current, or resistance) and range before making a measurement.
Never measure resistance or continuity on a live circuit.
When measuring current, always connect the multimeter in series with the circuit and ensure the power is off before connecting.
When measuring voltage, always connect the multimeter in parallel with the circuit.
Avoid touching the metal tips of the test leads when the multimeter is connected to a live circuit.
Use insulated test leads that are in good condition.
Do not exceed the maximum input ratings of the multimeter.

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 name some tools used in electrical or electronic work. The teacher then introduces the topic “Electronic Measuring Instruments” and specifically the multimeter, explaining that it is a versatile tool for checking electrical quantities.
Pupils’ Activity: Pupils respond to the teacher’s questions and listen attentively to the introduction.
Learning Point: Pupils recall prior knowledge of tools and are introduced to the lesson topic.

Step 2: Definition and Uses of a Multimeter

Time: 7 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher defines a multimeter and demonstrates how to identify its parts (display, function switch, input jacks) using a digital multimeter. The teacher then explains its various uses in electronics.
Pupils’ Activity: Pupils observe the multimeter demonstration, take notes, and ask questions for clarification.
Learning Point: Pupils understand what a multimeter is and its general applications.

Step 3: Measuring Current

Time: 8 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher explains the procedure for measuring current using a multimeter, emphasizing that it must be connected in series and the circuit must be off before connecting. The teacher demonstrates this with a simple circuit.
Pupils’ Activity: Pupils observe the demonstration, note the steps, and understand the series connection for current measurement.
Learning Point: Pupils learn the correct method for measuring current with a multimeter.

Step 4: Measuring Voltage

Time: 7 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher explains the procedure for measuring voltage, highlighting that it is connected in parallel. The teacher demonstrates measuring voltage across a battery or component in a simple circuit.
Pupils’ Activity: Pupils watch the demonstration, record the steps, and grasp the parallel connection for voltage measurement.
Learning Point: Pupils learn the correct method for measuring voltage with a multimeter.

Step 5: Measuring Resistance

Time: 6 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher explains and demonstrates how to measure resistance of a disconnected component (e.g., a resistor) using the multimeter, emphasizing that the component must not be in a live circuit.
Pupils’ Activity: Pupils observe the demonstration and understand how to measure resistance.
Learning Point: Pupils understand how to measure the resistance of a component.

Step 6: Safety Precautions

Time: 5 minutes
Teaching Skill: Discussion/Emphasis
Teacher’s Activity: The teacher discusses the important safety precautions that must be observed when using a multimeter, explaining the reasons behind each precaution.
Pupils’ Activity: Pupils listen, ask questions, and contribute to the discussion on safety.
Learning Point: Pupils learn about the critical safety measures for using electronic measuring instruments.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

What is a multimeter?
Mention three uses of a multimeter.
Briefly describe how to measure current in a circuit using a multimeter.
State any two safety precautions to observe when using a multimeter.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the importance of multimeters and safe practices. The teacher assigns homework: “Draw a diagram of a digital multimeter and label its main parts.”
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils consolidate their understanding and are given an assignment to reinforce learning.

Lesson Keywords

Multimeter – An electronic instrument that combines the functions of an ammeter, voltmeter, and ohmmeter to measure current, voltage, and resistance.
Current – The flow of electric charge, measured in Amperes (A).
Voltage – The electrical potential difference between two points, measured in Volts (V).
Resistance – The opposition to the flow of electric current, measured in Ohms (Ω).
Continuity – A test to check if an electrical path is complete or broken.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide more complex circuits for measurement practice. For those who need more support, the teacher can offer one-on-one guidance during practical demonstrations and provide simplified diagrams or step-by-step guides. Peer teaching can also be encouraged, where faster learners assist their classmates.

Note for teachers using this lesson plan

Ensure that functional multimeters and simple, safe circuits are available for practical demonstration. Emphasize safety precautions repeatedly throughout the lesson. Encourage pupils to actively participate in demonstrations and ask questions. Practical application is key to understanding this topic.