Understanding Galvanic Cells

I am an electronics guy and not into chemistry so please forgive my ignorance.


A Galvanic Cell is meant to act like a pump, separating positive and negative charges, and thereby creating an EMF. Obviously energy has to be expended in this process.


All my reading tells me that this occurs on account of redox reactions.


If I have understood right, redox reactions happen because of the chemical properties of elements and their atomic structures, and on account of the need for some elements to acquire or get rid of electrons, basically in order to attain octet 'stability'.


Now I presume that this urge for 'stability' is based on the natural process whereby things trend towards their lowest energy states.


Now if this is so, how is it that in redox reactions, charges get forced apart, which requires the expenditure of energy to accomplish. Where, how and why does this energy come from ?


How do we get this free gift of energy from nature just because a chemical element strives towards energy 'stability' by filling an octet.


Obviously I am missing something.


Can someone patiently explain what happens in a redox reaction, and why ?


I request you to use simple examples for electrode and electrolyte materials.


