Basic Electronics Lesson03 Insulators,conductors and semiconductors

 Insulators,conductors and semiconductors

Hydrogen atom

A hydrogen atom has the simplest structure of all.The two video show what is the hydrogen atom and how hydrogen and other atoms iexist in nature.

Conductors

Conductors are the materials or substances which allow electricity to flow through them. They conduct electricity because they allow electrons to flow easily inside them from atom to atom. Also, conductors allow the transmission of heat or light from one source to another.

Examples of conductors include metals, aqueous solutions of salts (i.e., ionic compounds dissolved in water), graphite, and the human body. 

Many materials are used to transmit electrical energy, but those most frequently specified for types of conductors are copper, copper-covered steel, high strength copper alloys, and aluminum.

Insulators

 An insulator is a material which is a poor conductor of electricity or heat. Some common insulators include wood, plastic, glass, porcelain and Styrofoam; Styrofoam and plastic see wide use in household applications.

Semiconductors

Semiconductors are materials which have a conductivity between conductors (generally metals) and nonconductors or insulators (such as most ceramics). Semiconductors can be pure elements, such as silicon or germanium, or compounds such as gallium arsenide or cadmium selenide.

Have look at this video and you will understand why metals are conductors  of electricity.

Basic Electronics Lesson02 Voltage,Current and Resistance(Ohm's Law)

 Measurement of Voltage,Current and Resistance(Ohm's Law)

Electric charge and the coulomb

An electric current consists of  aflow of electrons.These electrons are negatively charged and are an important part of an atom.The coulomb is used to measure electric charge.The video clip below gives an illustration of this:-

Electric current and the ampere

 You may have already used a filament lamp rated at 6V,0.06A(60mA).

The ampere is used to indicate the strength of  a current,and is measured in units of coolomb per second.In other words,electric current is the rate at which electric charge in coulomb moves through acircuit.It is easy to remember that one ampere is electric charge flowing at the rate of one coulomb per second,or 1A =1 coulomb/second = 1 C/s.

The 6V ,60mA  filament lamp will give  1A is 1 coulomb per second,60 mA=0.06 colomb per second.
.The video clip below gives an illustration of this:-

The letter I is the symbol used for electric current 

What the volt  measures?

The electromotive force of battery is the electrical force between its terminal which makes current flow round a circuit connected to it.The volt is the unit for measuring e.m.f.; for example we say the emf of a battery is 9 volts.

The potential(p.d.) is the difference of electrical force,measured in volts,between the terminals of a component which makes the current flow throughthe component.The  volt is the unit of e.m.f. and p.d.and it is measured using a voltmeter which is connected in  parallel with the component through which the current flows.

Proteus diagram