Electrical Circuits (Module 1)

Basic Electrical Ideas and Units

Electricity

The invisible energy that constitutes the flow of electrons in a closed circuit to do work. It is a form of energy that can be easily converted to any other form.

1600

what year does William Gilbert studied magnetic phenomena and demonstrated that the Earth itself was a huge magnet, by means of his "terrella" experiment. He also studied the attraction produced when materials were rubbed, and named it the "electric" attraction. From that came the word "electricity" and all others derived from it.

William Gilbert

 Father Of Electricity

 The Word “Electricity” Was Coined By him who based it on the Greek Word For Amber.

Benjamin Franklin

In 1752, he proved that lightning and the spark from amber were one and the same thing.

Luigi Galvani

In 1786, he found that when the leg of a dead frog was touched by a metal knife, the leg twitched violently. He thought that the muscles of the frog must contain electricity.

Alessandro Volta

By 1792, he disagreed to Galvani: he realized that the main factors in galvani's discovery were the two different metals - the steel knife and the tin plate - upon which the frog was lying. He showed that when moisture comes between two different metals, electricity is created.

Alessandro Volta

He invented the first electric battery, the voltaic pile, which he made from thin sheets of copper and zinc separated by moist pasteboard.

Alessandro Volta

He showed that electricity could be made to travel from one place to another by wire, thereby making an important contribution to the science of electricity. The unit of electrical potential is named after him.

Michael Faraday

He discovered electromagnets. He had discovered the first method of generating electricity by means of motion in a magnetic field. He also realized that the electric force is transmitted by an electric field.

James Watt

inventor of the steam condensing engine. His improvements to steam engines were patented over a period of 15 years, starting in 1769, and his name was given to the electric unit of power, the watt.

Andre Marie Ampere

first to explain the electro- dynamic theory. His name is used for the unit of electric current.

George Ohm

published "the galvanic circuit investigated mathematically". His name has been given to the unit of electrical resistance.

Static and Current Electricity

Two Main Types of Electricity

Static Electricity

involves electrons that are moved from one place to another, usually by rubbing or brushing. It is nothing but the contact between equal amount of protons and electrons (positively and negatively charged subatomic particles).

Current Electricity

involves the flow of electrons in a conductor. It is a flow of electric charge across an electrical field. This current is lead through a conductor.

Good conductors

the ones which let the electric charge flow through them

bad conductors

the ones which resists the electric charge

Frictional Electricity

It can be produced by rubbing certain dissimilar materials together.

piezoelectricity

Electricity produced from pressure. If a crystal made of this material is placed between two metal plates and pressure is exerted on the plates, an electric charge will be develop but the amount of charge will depend on the amount of pressure exerted.

Electric cells

electricity produced by chemical reactions.

photoelectric effect

The electricity is produced by light striking photosensitive materials. These materials release electrons when excited by light under the right conditions. These releases of electrons are called

Electricity Produced from Magnetism depends on

a. the number of turns in coil

b. the speed with which relative motions of the coil and the magnet take place

c. the strength of the magnet

Matter

made up of atoms

ELEMENT

A substance that cannot be decomposed any farther by chemical reaction

ATOM

Smallest part that an element can be reduced to and still keeping the chemical properties of the element. It is the smallest building block of matter.

COMPOUND

A combination of two or more elements.

MOLECULE

It is the smallest particle that a compound can be reduced to before it breaks down to its elements.

ELECTRONS

Negatively charged particles that revolve around the nucleus of an atom. It is one of the lightest particles with a known mass of about 9.109 x 10-31 kg.

PROTONS

Positively charged particles that stays in the nucleus of an atom. Very small, but it is fairly massive compared to the other particles that make up matter. The mass of one proton is 1.673 x 10-27 kg.

NEUTRONS

Particles having no charge. They are about the same size as protons but their mass is slightly greater, 1.675 x 10-27 kg

NUCLEUS

The central part of the atom where the protons and neutrons are located.

ATOMIC NUMBER

Represents the number of electrons or protons of an atom.

ATOMIC MASS

Represents the sum of protons and neutrons of an atom.

VALENCE ELECTRONS

Electrons found in the outermost shell or orbit of an atom.

CONDUCTORS

electric charges are free to move through these material.

Electrolytes & Semiconductors

Types of Conductors

electrolytes

type of conductor where both negative and positive charges can move.

semiconductors

In-between conductors and insulators in their ability to conduct electricity

INSULATORS

They are made of materials, generally non- metals, that have very few or no “free electrons” float about within their basic atom structure because the electrons in the outer valence shell are strongly attached by the positively charge inner nucleus.

electric circuit

an interconnection of electrical elements and each component of the circuit is known as an element.

Direct current (DC)

an electric current that is uni-directional, so the flow of charge is always in the same direction. the direction and amperage of direct currents do not change. It is used in many household electronics and in all devices that use batteries. Anything that works with a battery works here

Open Circuit

implies that the two terminals are points are externally disconnected, which is equivalent to a resistance R=∞ . This means that zero current can flow between the two terminals, regardless of any voltage difference.

Short Circuit

implies that the two terminals are externally connected with resistance R=0 , the same as an ideal wire. This means there is zero voltage difference for any current value.

ammeter

an instrument used to measure current and must be connected in series with the circuit.

voltmeter

an instrument used for measuring electric potential difference between two points in an electric circuit. and must be connected in parallel with the part of the circuit whose potential difference is required.

wattmeter

an instrument for the measurement of power in an electrical circuit.

ohmmeter

an instrument for measuring resistance.

multimeter

or universal instrument, may be used to measure voltage, current and resistance.

Charge or Electrical Charge

an electrical property of the atomics particles of which matter consists, measured in Coulombs(C)

1 electron = ____ Coulombs

−1.602x10−19 C

1 proton = ____ C

1.602x10−19 C

1 coulomb (C )= _____ electrons or protons

6.24 x 1018 electrons or protons

1\. Direct Current (DC)

2\. Alternating Current(AC)-

TYPES OF CURRENT

Direct Current (DC)

is a current that remains constant with time.

Alternating Current(AC)

is a current that varies sinusoidally with time.

VOLTAGE

Also known as electromotive force (emf); electric pressure; potential difference.

DC Voltage

commonly produce by batteries

AC Voltage

produced by electric generator

OHM’S LAW

It is a states that the current flowing in an electric circuit is directly proportional to the impressed emf applied to the circuit and inversely to the equivalent resistance of the said circuit.

POWER

the time rate of expending or absorbing energy, measured in watts (W) or J/s

Energy

the capacity to do work.

Kilowatt-hour (kW-hr)

unit in which electrical energy is sold to a consumer.