# Lesson Notes By Weeks and Term - Senior Secondary 1

Safety device fuse

Term: 3rd Term

Week: 6

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject:      Physics

Topic:-       Safety device fuse

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Define fuse
2. List and explain types of fuse
3. Determine faults in a circuit

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher reviews the previous lesson on solar energy Students pay attention STEP 2 EXPLANATION He defines and explains fuse. He lists and explains the types of fuse Students pay attention and participates STEP 3 DEMONSTRATION He explains how to detect faults in a circuit Students pay attention and participate STEP 4 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

FUSE

Fuse is a protective device, designed to melt at the passage of excess electric current through it.

It can also be defined as a device for opening circuit, by means of a conductor designed to melt when an excessive current flows along it.

The conductor actually designed to melt is called fuse element.

Fuse element is the part of the fuse that is designed to melt and then open the cct

CURRENT RATING OF A FUSE

It is the minimum current which the fuse will carry for an indefinite/ unlimited period without deterioration of the fuse element

FUSING CURRENT

It is the minimum current that will cause the fuse element to heat up and melt/ rapture or blow.

FUSING FACTOR

It is the ratio of the fusing current upon the current rating.

Fusing factor = fusing current/ current rating

TYPES OF FUSE

FUNCTIONS OF FUSE

1. Acts as a barrier between the electric circuit and the human body
2. Prevents device failure due to faulty circuit operation
3. Fuse prevents short-circuits
5. Prevents damage that is caused due to mismatched loads

DETECTING FAULT IN ELECTRIC CIRCUIT

1. Merger tester – insulation resistance test
2. Test bell – polarity test
3. Earth-loop impudence tester – test for earthling
4. Continuity tester – test for continuity

EVALUATION:   1. Define fuse

1. List some types of fuse
2. What are ways one can detect faults in an electric circuit?

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively