There is a necessity to discuss a few important terms here before we move on to subsequent chapters.

Current

It is simply the flow of electrons. A continuous flow of electrons or charged particles, can be termed as Current. It is indicated by I or i. It is measured in Amperes. This can be alternating current AC or direct current DC.

Voltage

It is the potential difference. When there occurs a difference in potentialities, between two points, there is said to be a voltage difference, measured between those two points. It is indicated by V. It is measured in Volts.

Resistance

It is the property of opposing the flow of electrons. The possession of this property can be termed as resistivity. This will be discussed later in detail.