Meaning of Electrical loads for JSS 1

Class: JSS 1
Term: First Term
Week: 3
Age: 12 years
Duration: 45 minutes
Subject: Solar PV Installation and Maintenance
Curriculum Theme: Solar Photovoltaics System for Electricity Generation
Focal competence: Demonstrate the knowledge of Solar Photovoltaics System and safety precautions
Key competencies/values: Communication; Collaboration; ICT and Digital Competencies
Skills:

• Using name plates of appliances, functions or power source to determine their category of load

Previous Lesson: Solar PV and Electricity generation
Topic: Electrical Appliances Power Load/Loads Sizing
Subject Matter: Meaning of Electrical loads, Meaning of Alternating Current (AC) and Direct Current (DC) Power

Specific Objectives

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

Cognitive Domain

• define Electrical loads;
• define Alternating Current (AC) and Direct Current (DC) Power;
• explain electrical loads;
• state the characteristics of types of electrical loads.

Affective Domain

• Appreciate the importance of understanding electrical loads in solar PV systems.
• Participate actively in class discussions on electrical concepts.

Psychomotor Domain

• Identify examples of electrical loads from their environment.
• Distinguish between AC and DC power sources.

Social Domain

• Collaborate with peers to discuss and identify different types of electrical loads.

Reference Materials

The following resources were used in planning this lesson:

• 2025 Revised 9 Years Basic Education Curriculum
• Relevant State Unified Scheme of Work
• Basic Electricity and Electronics for Junior Secondary Schools, Book 1
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• Approved curriculum resource/material
• Charts showing different electrical appliances
• Pictures or diagrams illustrating AC and DC waveforms
• Examples of appliance nameplates (e.g., iron, fan, light bulb)

Rationale for the Lesson

Understanding electrical loads and the difference between AC and DC power is foundational for anyone working with solar PV systems. This lesson provides students with the basic knowledge required to correctly size and manage electrical systems, ensuring efficiency and safety in power installations. It prepares them for more advanced topics in renewable energy.

Prerequisite/Previous Knowledge

Students should have a basic understanding of electricity, simple circuits, and common electrical appliances in their homes.

Lesson Content/Board Summary

Electrical Appliances Power Load/Loads Sizing

Meaning of Electrical Loads

An electrical load is any component or device that consumes electrical energy and converts it into another form of energy, such as heat, light, or motion. Simply put, it is anything that uses electricity to perform a function.

1. Examples of Electrical Loads:
   1. Light bulbs (convert electrical energy to light and heat)
   2. Electric fans (convert electrical energy to mechanical motion)
   3. Refrigerators (convert electrical energy to cool air)
   4. Television sets (convert electrical energy to light and sound)
   5. Electric irons (convert electrical energy to heat)

Explanation of Electrical Loads (Types/Characteristics)

Electrical loads can be broadly categorized based on their characteristics, which affect how they interact with an electrical power supply.

1. Resistive Loads:
   1. These loads convert nearly all electrical energy into heat.
   2. They do not cause a phase shift between voltage and current.
   3. Examples: Incandescent light bulbs, electric heaters, toasters, electric irons.
2. Inductive Loads:
   1. These loads have coils of wire that create magnetic fields, causing the current to lag behind the voltage.
   2. They require more power to start up (inrush current).
   3. Examples: Electric motors (in fans, refrigerators, pumps), transformers, fluorescent lights.
3. Capacitive Loads:
   1. These loads store energy in an electric field and cause the current to lead the voltage.
   2. They are less common in typical household appliances but found in certain electronic devices and power factor correction circuits.
   3. Examples: Capacitors, certain types of electronic power supplies.

Meaning of Alternating Current (AC) Power

Alternating Current (AC) is a type of electrical current where the flow of electric charge periodically reverses direction. This is the most common form of electricity used in homes and businesses because it can be easily transmitted over long distances at high voltages and then stepped down to safer voltages for use.

1. Characteristics of AC:
   1. Direction of current flow changes periodically.
   2. Voltage level can be easily changed using transformers.
   3. Suitable for long-distance power transmission.
   4. Typically generated by power plants.

Meaning of Direct Current (DC) Power

Direct Current (DC) is a type of electrical current where the flow of electric charge is always in one direction. DC power is commonly found in batteries, solar panels, and electronic devices.

1. Characteristics of DC:
   1. Direction of current flow is constant.
   2. Voltage level is generally fixed and harder to change without complex electronics.
   3. Less efficient for long-distance power transmission at low voltages.
   4. Examples: Batteries, solar panels, fuel cells, rectifiers.

Teaching Methods/Instructional Techniques

Discussion, Demonstration, Guided Practice, Question and Answer, Explanation, Observation

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Engaging/Questioning

Teacher’s Activity: The teacher greets the students and asks them to name some electrical appliances they use daily. The teacher then asks what these appliances do with electricity.

Students’ Activity: Students name appliances like fans, bulbs, TV, and mention they use electricity to work.

Learning Point: Everyday electrical appliances

Step 2: Define Electrical Loads

Time: 8 minutes

Teaching Skill: Explanation/Definition

Teacher’s Activity: The teacher guides students to define electrical loads, using examples from their previous responses. The teacher explains that anything that consumes electricity is a load.

Students’ Activity: Students listen, contribute to the definition, and identify more examples of electrical loads.

Learning Point: Definition of electrical loads

Step 3: Explain Electrical Loads (Types/Characteristics)

Time: 8 minutes

Teaching Skill: Elaboration/Classification

Teacher’s Activity: The teacher explains the different types of electrical loads (resistive, inductive, capacitive) and their characteristics, providing simple examples for each. The teacher uses appliance nameplates to illustrate.

Students’ Activity: Students listen, observe the nameplates, and ask questions for clarification on load types.

Learning Point: Types of electrical loads

Step 4: Define Alternating Current (AC)

Time: 7 minutes

Teaching Skill: Explanation/Illustration

Teacher’s Activity: The teacher introduces Alternating Current (AC), explaining its meaning and characteristics. The teacher may draw a simple AC waveform on the board or show a diagram.

Students’ Activity: Students listen, observe the diagram, and participate in discussion about AC power.

Learning Point: Meaning of AC power

Step 5: Define Direct Current (DC)

Time: 7 minutes

Teaching Skill: Explanation/Illustration

Teacher’s Activity: The teacher introduces Direct Current (DC), explaining its meaning and characteristics. The teacher may use examples like batteries and solar panels.

Students’ Activity: Students listen, identify DC sources, and ask questions.

Learning Point: Meaning of DC power

Step 6: Differentiate AC and DC

Time: 3 minutes

Teaching Skill: Comparison/Summarization

Teacher’s Activity: The teacher briefly summarizes the key differences between AC and DC power, reinforcing the characteristics taught.

Students’ Activity: Students recall and state the differences between AC and DC.

Learning Point: AC vs. DC comparison

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

1. What is an electrical load?
2. Give two examples of resistive loads.
3. Define Alternating Current (AC).
4. State one characteristic of Direct Current (DC).

Students’ Activity: Students answer orally and in writing.

Learning Point: Understanding electrical concepts

Step 8: Note-Taking

Time: 4 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes on electrical loads and AC/DC power into their notebooks.

Students’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Recording lesson notes

Step 9: Conclusion

Time: 3 minutes

Teaching Skill: Consolidation

Teacher’s Activity: The teacher briefly recaps the lesson, emphasizing the importance of understanding electrical loads and the difference between AC and DC in solar PV applications. The teacher encourages students to observe appliances at home.

Students’ Activity: Students listen and ask any final questions.

Learning Point: Lesson recap and application

Continuous Assessment/Further Study

Type: Homework

Instruction: Answer the following questions in your notebook.

1. List five electrical appliances found in your home and state if they are primarily resistive or inductive loads.
2. Identify two sources of AC power and two sources of DC power.
3. Explain in your own words why it is important to know the type of load an appliance represents when designing a power system.

Lesson Keywords

• Electrical Load – A device that consumes electrical energy.
• Alternating Current (AC) – Electric current that periodically reverses direction.
• Direct Current (DC) – Electric current that flows in only one direction.
• Resistive Load – Converts electrical energy mainly to heat.
• Inductive Load – Creates magnetic fields, causing current to lag voltage.
• Capacitive Load – Stores energy in an electric field, causing current to lead voltage.

Differentiation

For weaker learners, provide simplified definitions and focus on identifying common examples of AC, DC, and electrical loads. Use more visual aids and encourage peer support. For faster learners, challenge them to research more complex examples of loads or the applications of AC and DC in different technologies beyond household use.

Suggested Lesson Videos

For further understanding, search on YouTube for:

• “What is an electrical load for kids”
• “Difference between AC and DC current explained”
• “Types of electrical loads explained”

Teacher Guide for Using This Lesson Plan

Before the lesson, gather visual aids such as actual appliance nameplates (e.g., from an old fan, iron, or light bulb packaging) or clear pictures of them. Prepare simple diagrams of AC and DC waveforms if you plan to draw them. Begin by connecting the lesson to students’ everyday experiences with electrical appliances. Guide them through defining electrical loads and then explaining the different types with practical examples. Clearly differentiate between AC and DC power, using real-world examples like wall sockets for AC and batteries for DC. During the explanation of load types, ensure students grasp the basic concept rather than complex electrical theory. Encourage students to ask questions and participate actively. Allow sufficient time for note-taking from the Board Summary after the concepts have been thoroughly explained and understood. Conclude by reinforcing the practical relevance of this knowledge for their future studies in solar PV.