Subject Name And Code : Elements of Electrical Engineering(2110005)

Active Learning Assignment

Topic : Basic Electrical Concept

Guided by : Prof. Supraja Giddaluru

Branch : Electrical

Division : F2 Sem : 1st

Academic Year : 2014(odd)

Prepared By:

Name

• Harshid Panchal

• Harsh Prajapati

• Manthan Rajput

Enrollment no.

140120109023

140120109042

140120109057

CURREN

T• Current(I) is a measure of how much charge(Q) is

flowing through a circuit at a particular moment.

• Or its another definition is:

Electric current is the rate of charge flow past a

given point in an electric circuit, measured in

Coulombs/second which is named Amperes. In most

DC electric circuits, it can be assumed that the

resistance to current flow is a constant so that the

current in the circuit is related to voltage and

resistance by Ohm's law. The standard

Abbreviations for the units are 1 A = 1C/s.

I=Q─t (ᴀ)

TYPES OF CURRENT

Alternating Current(AC):-

In AC, electrons keep switching

directions, sometimes going "forwards" and

then going "backwards.“

Safe to transfer over longer city distances

and can provide more power.

The frequency of alternating current is

50Hz or 60Hz depending upon the country.

It reverses its direction while flowing in a

circuit.

It is the current of magnitude varying

with time.

Power factor Lies between 0 & 1.

It’s types are Sinusoidal, Trapezoidal,

Triangular, Square.

Direct Current(DC):-

In DC, the electrons flow steadily in a

single direction, or "forward.

Voltage of DC cannot travel very far until

it begins to lose energy.

The frequency of direct current is zero.

It flows in one direction in the circuit.

It is the current of constant magnitude.

Power Factor it is always 1.

It’s types are Pure and pulsating.

AMMETER

An ammeter is a measuring instrument used to measure the electric

current in a circuit. Electric currents are measured in amperes (A), hence

the name. Instruments used to measure smaller currents, in the

milliampere or microampere range.

VOLTAG

EVoltage, also called electromotive force, is a

quantitative expression of the potential difference in

charge between two points in an electrical field.

•It is possible to have voltage without current, but current

cannot flow without voltage.

•Voltage is a measure of the energy carried by the charge.

•The proper name for voltage is potential difference or p.d.

for short.

•Voltage is supplied by the battery (or power supply).

•Voltage is measured in volts, V.

•Voltage is measured with a voltmeter, connected in parallel.

•The symbol V is used for voltage in equations.

The switch is closed making

a complete circuit so

current can flow.

The switch is open so the

circuit is broken and

current cannot flow.

Without the cell there is no

source of voltage so

current cannot flow.

VOLTMETER

A voltmeter is an instrument used for measuring electrical potential

difference between two points in an electric circuit. Analog voltmeters

move a pointer across a scale in proportion to the voltage of the circuit;

digital voltmeters give a numerical display of voltage by use of an analog

to digital converter.

POWER•Electric power is the rate at which electric energy is

transferred by an electric circuit.

•The SI unit of Power is the watt, one joule per second.

•Electric power is usually produced by electric generators,

but can also be supplied by chemical sources such as electric

batteries.

•Electric power, like mechanical power, is the rate of doing

work, measured in watts, and represented by the letter P.

where

•Q is electric charge in coulombs

•t is time in seconds

•I is electric current in amperes

•V is electric potential or voltage in volts

RESISTOR

Resistance is a property of material due to which it opposes the flow of current through it.

When electrons flow through any material, they collide with each other which gives rise to opposition to the flow of current.

The unit of resistor is ohm(Ω).

The resistance of a conductor will be 1Ω when it allows 1 A current to flow through it on application of 1 V across its material.

The resistance of conducting material is found to …

(1) be directly proportional to the length l of the material,

(2) be inversely proportional to the cross-sectional area of the material.

(3) depend on the nature of material.

(4) depend upon the temperature.

Therefore,

R ∞ l/a

or R = ρl/a

Where,

R=resistance in Ω

l=length in m

a =cross section area in m²

ρ= resistivity in Ω-m

INDUCTOR

An inductor is made of a coil of conducting wire.

An inductor is a passive element designed to

store energy in the magnetic field while a

capacitor stores energy in the electric field.

dt

diL

dt

dv

CAPACITOR

A capacitor consists of two conducting plates

separated by an insulator (or dielectric).

The symbol use for capacitor in the

circuit diagram is ::

A capacitor is a two terminal circuit element that has a current

through its terminals which is proportional to the derivative of

the voltage across its terminals.

The coefficient of this proportionality is the defining

characteristic of a capacitor.

A capacitor is the device that we use to model the effect of

electric fields on circuit variables.

The energy stored in electric fields has effects on voltage and

current.

Three factors affecting the value of capacitance:

1. Area: the larger the area, the greater the capacitance.

2. Spacing between the plates: the smaller the spacing, the greater the capacitance.

3. Material permittivity: the higher the permittivity, the greater the capacitance.

d

AC

ε

(F/m)10854.8

ε

12

0

0

r

d

ACWhere,

The relation between the charge in plates and the voltage across a

capacitor is given below.

Cvq C/V1F1

ELECTRICAL ENERGY SOURCES

Electricity

Electricity is very important in our lives.

We would find it very hard to do without it.

There are so many things in our homes that are powered by

electricity that we have begun to depend on them.

Imagine you woke up this morning and had no electricity.

What difference would it make to

your normal morning routine?

Solar energy

Energy radiates from the sun and the light rays can be captured

with photovoltaics and semiconductors. Mirrors can be used to

concentrate the power, and the sun’s heat is also a thermal source.

Water Electricity

Water Electricity is electricity obtained from hydropower. Most

hydroelectric power comes from the potential energy of dammed water

driving a water turbine and generator. Less common variations make use

of water's kinetic energy or undammed sources such as tidal power.

Hydroelectricity is a renewable energy source.

Wind Energy

Wind is a form of solar energy. Winds are caused by the uneven heating of

the atmosphere by the sun, the irregularities of the earth's surface, and

rotation of the earth. Wind flow patterns are modified by the earth's

terrain, bodies of water, and vegetative cover. This wind flow, or motion

energy, when "harvested" by modernwind turbines, can be used to

generate electricity.

Chemical energy

This is stored, or “potential,” energy. Releasing chemical energy

from in carbon-based fuels generally requires combustion – for

example the burning of coal, oil, natural gas, or a biomass such as

wood.

Like is carbon battery

Thermal energy

Typical sources of thermal energy are heat from underground hot springs,

combustion of fossil fuels and biomass (per above) or industrial processes.

Nuclear energy

This is the energy stored in the bonds inside atoms and molecules.

When nuclear energy is released, it can emit radioactivity and heat

(thermal energy) as well.

References :