What is a Resistor?

Symbol: W

Dictionary.com:

resistor n : an electrical device that resists the flow of electrical current

Encyclopedia.com :

Resistor: two-terminal electric circuit component that generates heat by offering opposition to an electric current. The most common forms of resistors are made from fine wires of special alloys wound onto cylindrical forms or from a molded composition material containing carbon and other substances in varying amounts. Resistors are rated for the maximum amount of power that they can safely handle.

Formula: V=R * I

  • V=Voltage
  • R=Resistance
  • I=Current

 
The connections in electric circuits can be classified broadly as serial connections and parallel connections which are shown. When several resistors are connected together, the combined resistance value will be different in serial and parallel connections as follows:

In the case of serial connection:

In the case of parallel connection: