Voltage, Current, Resistance & Ohm's Law

The three basic principles of this entry can be explained using electrons, or more specifically, the charge they create:

• Voltage is the difference in charge between two points.
• Current is the rate at which charge is flowing.
• Resistance is a material’s tendency to resist the flow of charge (current).

Voltage

Voltage is a specific measure of potential energy that is always relative between two points. The different in charge between two points is called Voltage. The unit “volt” is named after the Italian physicist Alessandro Volta who invented what is considered the first chemical battery. Voltage is represented in equations and schematics by the letter “V”.

Current

Current is the flow of electrons/charged particles

Resistance

Resistance is how difficult it is for the charges to flow through an electrical component or from one point to another in an electrical circuit. The SI unit of electrical resistance is the ohm (Ω). Resistance was discovered by Georg Simon Ohm, who was born in Bavaria in 1787 and worked in obscurity for much of his life, studying the nature of electricity using metal wire that he had to make for himself (you couldn’t truck on down to Home Depot for a spool of hookup wire back in the early 1800s). Despite his limited resources and inadequate mathematical abilities, Ohm was able to demonstrate in 1827 that the electrical resistance of a conductor such as copper varied in inverse proportion with its area of cross-section, and the current flowing through it is proportional to the voltage applied to it, as long as temperature is held constant.

Ohm's Law

Combining the elements of voltage, current, and resistance, Ohm developed the formula:

V = I x R

• V = Voltage in volts
• I = Current in amps
• R = Resistance in ohms

Related links:

1. Reference
2. Reference
3. Reference
4. Reference