ELECTRICAL ENERGY J S 3

TERM: FIRST TERM

SUBJECT: BASIC SCIENCE

CLASS: JSS 3

WEEK 6

TOPIC: ELECTRICAL ENERGY J S 3

WHAT IS LIGHT

Light can be defined as a form of energy which produces electromagnetic radiation capable of causing visual sensation. Light is a kind of electromagnetic wave (waves that can travel in vacuum). Light is the fastest substance known to man. ELECTRICAL ENERGY J S 3

ENERGY

Energy is a fundamental concept in physics and refers to the capacity of a system to do work or produce a change. It comes in many forms, including mechanical, thermal, chemical, nuclear, electromagnetic, and others.

WHAT IS LIGHT ENERGY

Electrical energy is a form of energy that results from the movement of charged particles, typically electrons, through a conductor, such as a wire. It is a type of energy that is readily converted into other forms, such as light, heat, or mechanical energy. Electrical energy is commonly generated by power plants using various methods such as burning fossil fuels, nuclear reactions, or harnessing renewable energy sources like wind, solar, hydroelectric, and geothermal power.

FLOW OF ELECTRON

The flow of electric current refers to the movement of electrically charged particles, typically electrons, through a conductor in a closed circuit. Electric current is measured in units called amperes (A) and is defined as the rate of flow of charge past a given point in the circuit.

In a closed circuit, electric current flows from the negative terminal of a voltage source (such as a battery or generator), through the conductive pathway (usually wires), and returns to the positive terminal of the voltage source. This flow of electrons constitutes an electric current.

The flow of electric current is governed by Ohm’s Law, which states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R) between them.

Mathematically, Ohm’s Law is expressed as:

$I = R V$

Where:

$I$ is the electric current in amperes (A).
$V$ is the voltage across the conductor in volts (V).
$R$ is the resistance of the conductor in ohms ( $Ω$ ).

TYPES OF CURRENT

there are primarily two types of electric current:

Direct Current (DC):
- Direct current is characterized by the continuous flow of electric charge in one direction.
- The magnitude and direction of the current remain constant over time.
- DC is typically produced by sources such as batteries, solar cells, and rectifiers.
- It is commonly used in low-voltage applications, electronics, and certain types of motors.
Alternating Current (AC):
- Alternating current periodically reverses direction, causing the flow of electric charge to oscillate back and forth.
- AC is characterized by its sinusoidal waveform, where the current alternates between positive and negative values.
- AC is generated by power plants and distributed through power grids for most household and industrial applications.
- It is preferred for long-distance transmission due to its ability to be easily transformed to higher or lower voltages using transformers.
- AC is used in a wide range of applications, including powering appliances, lighting, motors, and industrial machinery.

These two types of electric current have distinct characteristics and applications, and they play essential roles in various aspects of modern electrical systems.

A FUSE

A fuse is a protective device used in electrical circuits to prevent damage to electrical components and wiring caused by excessive current flow. Its primary function is to interrupt the circuit by melting its fuse element when the current exceeds a predetermined level, known as the rated current or current rating.

Here are some key points about fuses:

Operation: When the current flowing through a fuse exceeds its rated value, the heat generated by the current causes the fuse element (often made of a metal or alloy with a low melting point) to melt, thereby opening the circuit and breaking the electrical connection.
Types: Fuses come in various types, including cartridge fuses, blade fuses, resettable fuses (such as thermal fuses and polymeric positive temperature coefficient (PPTC) devices), and others. Each type has its own characteristics and applications.
Protection: Fuses protect electrical circuits and devices from overcurrent conditions, such as short circuits and overloads, which can lead to overheating, fires, and damage to equipment.
Rating: Fuses are rated based on parameters such as current rating (the maximum current that the fuse can safely carry indefinitely), voltage rating (the maximum voltage at which the fuse can operate safely), and interrupting rating (the maximum fault current that the fuse can safely interrupt without causing damage).
Replacement: When a fuse blows or “trips” due to overcurrent, it must be replaced with a fuse of the same type and rating to ensure proper protection of the circuit.
Applications: Fuses are commonly used in various electrical systems and devices, including residential and commercial wiring, automotive circuits, industrial equipment, power distribution systems, and electronic devices.

A Circuit Breaker

A circuit breaker is a protective device designed to automatically interrupt electrical power in a circuit when it detects an over current condition, such as a short circuit or overload. Here’s an overview of circuit breakers:

Function: Circuit breakers serve a similar purpose to fuses but offer the advantage of being resettable after they trip. When an overcurrent occurs, the circuit breaker trips and interrupts the flow of electricity, thus protecting the circuit and connected devices from damage.
Operation: Circuit breakers consist of a switch mechanism and a tripping mechanism. The switch is typically operated manually or automatically, and it controls the flow of electricity through the circuit. The tripping mechanism detects abnormal currents and triggers the switch to open the circuit when necessary.
Types: There are several types of circuit breakers, including thermal-magnetic circuit breakers, magnetic circuit breakers, and electronic circuit breakers. Each type has its own characteristics and applications.
Ratings: Circuit breakers are rated based on parameters such as voltage rating, current rating, and interrupting rating. The current rating specifies the maximum current that the circuit breaker can carry continuously without tripping, while the interrupting rating indicates the maximum fault current that the circuit breaker can safely interrupt.
Applications: Circuit breakers are widely used in residential, commercial, and industrial electrical systems to protect wiring, equipment, and devices from overcurrent conditions. They are commonly found in distribution panels, breaker boxes, and electrical control panels.
Reset: After tripping, a circuit breaker can be manually reset by toggling its switch to the “off” position and then back to the “on” position. This restores power to the circuit once the underlying issue causing the overcurrent condition has been addressed.

Different between A fuse and A circuit Breaker

Circuit breakers are essential components of electrical safety systems, providing reliable protection against electrical hazards and ensuring the safe operation of electrical circuits and equipment.

Fuses and circuit breakers are both protective devices used in electrical circuits to prevent damage caused by overcurrent conditions, such as short circuits and overloads. While they serve a similar purpose, they have several differences in terms of operation, characteristics, and applications. Here’s a comparison between fuses and circuit breakers:

Operation:
- Fuse: A fuse contains a fuse element, typically made of a metal or alloy with a low melting point. When the current exceeds the rated value, the heat generated by the current melts the fuse element, causing the circuit to open and interrupting the flow of electricity.
- Circuit Breaker: A circuit breaker consists of a switch mechanism and a tripping mechanism. When an overcurrent condition occurs, the tripping mechanism detects it and triggers the switch to open, thereby interrupting the flow of electricity. Circuit breakers can be reset manually or automatically after tripping.
Resetting:
- Fuse: Fuses are one-time protective devices. Once the fuse element melts and interrupts the circuit, the fuse must be replaced with a new one to restore the circuit’s functionality.
- Circuit Breaker: Circuit breakers are resettable protective devices. After tripping due to an overcurrent condition, circuit breakers can be manually reset by toggling the switch to the “off” position and then back to the “on” position, restoring power to the circuit.
Life Cycle:
- Fuse: Fuses have a limited lifespan and need to be replaced each time they operate (i.e., when they blow due to an overcurrent condition).
- Circuit Breaker: Circuit breakers have a longer lifespan and can be reused multiple times after tripping, as long as they are not damaged or worn out.
Response Time:
- Fuse: Fuses generally have a faster response time than circuit breakers because they rely on the rapid heating and melting of the fuse element to interrupt the circuit.
- Circuit Breaker: Circuit breakers may have a slightly longer response time compared to fuses, as they need to detect the overcurrent condition and then trigger the switch to open the circuit.
Application:
- Fuse: Fuses are commonly used in low-voltage applications, automotive circuits, and specific industrial applications.
- Circuit Breaker: Circuit breakers are widely used in residential, commercial, and industrial electrical systems due to their resettable nature and ability to provide ongoing protection against overcurrent conditions.

In summary, while both fuses and circuit breakers offer protection against over current conditions, they differ in terms of operation, resetting capability, lifespan, response time, and application suitability. The choice between a fuse and a circuit breaker depends on factors such as the specific requirements of the electrical system, the type of over current protection needed, and the desired maintenance approach.

BASIC SCIENCE NOTE FOR J S 1