Ohm's Law

Probably the most important mathematical relationship between voltage, current and resistance in electricity is something called “Ohm’s Law”. A man named George Ohm published this formula in 1827 based on his experiments with electricity. As a school teacher, Ohm began his research with the new electrochemical cell, invented by Italian scientist Alessandro Volta. Using equipment of his own creation, Ohm found that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current. This relationship is known as Ohm's law.

Ohm's Law Formula / Equation

When we know the voltage and resistance, we can calculate the current.

Ohm's law definition

The resistor's current I in amps (A) is equal to the resistor's voltage V_R=V in volts (V) divided by the resistance R in ohms (Ω):

V is the voltage drop of the resistor, measured in Volts (V). In some cases Ohm's law uses the letter E to represent voltage. E denotes electromotive force.

I is the electrical current flowing through the resistor, measured in  Amperes (A)

R is the resistance of the resistor, measured in Ohms (Ω)

Voltage calculation

When we know the current and resistance, we can calculate the voltage.

The voltage V in volts (V) is equal to the to the current I in amps (A) times the resistance R in ohms (Ω):

Resistance calculation

When we know the voltage and the current, we can calculate the resistance.

The resistance R in ohms (Ω) is equal to the voltage V in volts (V) divided by the current I in amps (A):

Since the current is set by the values of the voltage and resistance, the Ohm's law formula can show that:

• If we increase the voltage, the current will increase.
• If we increase the resistance, the current will reduce.  

Learn more by watching this video:

“Invention is the most important product of man's creative brain. The ultimate purpose is the complete mastery of mind over the material world, the harnessing of human nature to human needs.”

― Nikola Tesla, My Inventions

What is Electricity?

Electricity 

is the foundation of technological civilization and modernization in our society. Without Electricity we revert to the stone age,  no household appliances, telephone, light bulb, television and other electric device.

Electric Circuit

in an interconnection of the electrical elements. A simple electric circuit is consist of 3 basic elements:

1. A source of electrical potential difference or voltage. (typically a battery or electrical outlet)
2. A conductive path which would allow for the movement of charges. (typically made of wire)
3. An electrical resistance (resistor) which is loosely defined as any object that uses electricity to do work. (a light bulb, electric motor, heating element, speaker, etc.)

Current

is a flow of electrical charge carriers, usually electrons. The common symbols for current is I. The standard unit is the ampere, symbolized by A.

Voltage

is the electric potential difference between two points, or the difference in electric potential energy of a unit charge transported between two points. Voltage is equal to the work done per unit charge against a static electric field to move a charge between two points. A voltage may represent either a source of energy (electromotive force), or lost, used, or stored energy.

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 sources such as electric batteries. Electric power is generally supplied to businesses and homes by the electric power industry.

Learning's 

      My learning in this 1st week in circuit is that many appliances (device) in our homes uses mains electricity to work. Without electricity our lives would be boring, no television , no computer games, no cellular phones, no radio. Modern society relies heavily on the convenience and versatility of electricity. It powers our light bulb for the safety of our house especially at night. When an electric charge builds up on the surface of an object it creates static electricity. You have probably experienced static electricity in the form of a small electric shock, which is what happens when the electric charge is quickly neutralized by an opposite charge. 

Electricity, simply put, is the flow of electric current along a conductor. This electric current takes the form of free electrons that transfer from one atom to the next. Thus, the more free electrons a material has, the better it conducts. so be careful of the electricity because our body is a good conductor.