Cell Potential of a electrochemical cell

Electrochemical cells have inheritance advantage of higher efficiency as compared to conventional source of electricity generation. In electro-chemical cell the chemical reaction is split in two separate half reactions known as oxidation half reaction and reduction half reaction.
There are two electrodes known as anode and cathode, at anode oxidation takes place while at cathode reduction takes place. During oxidation, electrons are released at the electrode and makes it negative charge while in reduction electrons are used, therefore cathode is positive charge.
As the two reactions are opposite, the potential of the cell is addition of potential of two electrode:
Ecell = E_anode (oxidation potential) + E_cathode (reduction potential)
as oxidation potential = -reduction potential
 Ecell = -E_anode (reduction potential) + E_cathode (reduction potential)
               E_cathode (reduction potential) - E_anode (reduction potential)