Conductors are material that easily allow electrical current pass through them with very-less opposition. Almost all metals are conductors. When ever you cut an electric wire, you can see copper or some other metal at its core. It’s because these metals can easily conduct electricity. Silver can conduct electricity better than copper; copper can conduct electricity better than gold. We don’t use them because they are tremendously Costly due to their scarcity. In cases where electrical circuit needs to be short, like in PC B’s and in IC’s, gold has been used. Gold is chosen over silver because it’s static and doesn’t retort
And / or corrode as quickly as silver. Examples of conductors are copper, silver, gold, aluminum, steel etc.
Insulators are that material that does not conduct electricity under normal conditions. For instance: air is an insulator. You don’t get electrocuted when forthcoming a plug point since air is an insulator. In irregular situations, air behaves like a conductor. For example, during a thunderstorm, extremely high voltage creates lightning bolts, which jump from one cloud to another or to the ground. At these excessive conditions, air will act as a conductor. Examples of insulators are plastic, rubber, paper, wood etc.
Semiconductors are materials that act like both conductors and insulators. In certain condition a semiconductor acts like a conductor. For example charcoal and graphite which are allotrope of Carbon act as conductor. Whereas diamond which has a different crystal structure act as an insulator. The conductivity of semiconductors can be improved
By adding certain impurities to them this is called doping. The conductivity may improve by pumping energy into semiconductor crystal in the form of heat or light. Example of is silicon, germanium etc.
A resistor is an electrical element that limits or controls the flow of electrical current in an electronic circuit. Resistors can also be used to afford an exact voltage for an active device such as a transistor.
A resistor has two terminals diagonally which electricity must pass, and is designed to drop the voltage of the current as it run from one terminal to the next. A resistor is primarily used to generate and maintain a known safe current within an electrical component. Unit of resistor is Ohm’s (Ω).
Imagine water flowing through a pipe. If we make the pipe thin then this will restrict the flow of water. If we force the water (current) through the narrow gap by increasing the pressure (voltage) then energy will be given off as heat. In addition, there will be an important difference in pressure (voltage) above and below the restriction.
In electronics we use a resistor when we need to reduce the voltage applied to a circuit.
A resistor is covered with paint or enamel, or covered in molded plastic to protect it. Because resistors are often too small to be written on, a standardized color-coding system is used to identify them.
The first three colors represent ohm value, and a fourth indicates the tolerance, or how close by percentage the resistor is to its ohm value. This is important for two reasons: the nature of resistor structure is imprecise, and if used above its maximum current, the value of the resistor can change or the unit itself can burn up.
Normally copper wire is used for transmission of current .Electrons normally rotate around the nucleus of each atom of copper in the wire, but when electrical pressure (that is the voltage) from a battery or generator is applied, some of these electrons are forced out of their orbits and pass from atom to atom along the length of the wire. These electrons are called free electrons and come from the outer orbit of the atom.
The amount of current depends on the number of electrons passing a given point in a circuit each second. It is measured in Amperes (A) using an apparatus called an Ammeter. An ammeter must be connected in series with other devices in a circuit. The letter I is used to signify the amount of current in a circuit.
Voltage is the potential energy that makes the electrical current flow in a circuit by pushing the electrons around. Voltage is like pressure on water in a pipe flowing from upper side to lower side .voltage means pressure on electrons to flow .The unit of voltage is volt shown as ‘v’. And it is measured by voltmeter.
Georg Simon Ohm was a German physicist born in Erlangen, Bavaria, on March 16, 1787. Using the results of his experiments, Georg Simon Ohm was able to describe the basic relationship between voltage, current, and resistance. These basic relationships are of such great significance, that they stand for the true beginning of electrical circuit analysis. And it is very big invention in electronics field.
Using apparatus of his own construction, Ohm determined that the current that flows through a wire is proportional to its cross sectional area and inversely proportional to its length or Ohm’s law.
In other words ohm’s law can be state as below:
Ohm’s law states that the current through a conductor between two points is directly proportional to the potential difference across the two points, and inversely proportional to the resistance between them.
The mathematical equation that describes this relationship is:
I = V/R
Where I is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm’s law states that the R in this relation is constant, independent of the current.