Ohm's Law

Ohm’s law is one of the most important ideas to understand in electronics. It describes the relationship between voltage, current and resistance. Ohm’s law was first presented in a 1827 treatise by German physicist Georg Ohm.

Voltage

Voltage is the measure of electrical pressure or potential. The greater the pressure the more current can pass
through the same conductor. The unit of Voltage is the Volt and is named for the Italian physicist Alessandro Volta.

Current

Current is the measurement of electrons through an electrical conductor. The unit for measuring current is the Amp or Ampere, named for the French physicist André-Marie Ampère. 

Resistance

Resistance is the measure of how much a material resists or slows down an electrical current flowing through it. Every material including conductors have some resistance. The unit of resistance is the Ohm.