The Basic Cell

Discussion in 'General Electronics Chat' started by greenberet, Nov 19, 2006.

  1. greenberet

    Thread Starter New Member

    Nov 13, 2006
    9
    0
    Well you see suppose you connected a 1.5 V cell to a 0.1 ohm resistor, using ohm's law you are to get a current of 15A. But definitely you cant get that, because a small cell cannot deliver so much power.

    So, i read that a cell has a sort of internal resistance which drops the terminal voltage to 0V when an attempt is made to draw excess power.

    But, thats the way circuit makers explain it.

    I want to know what happens at electron level.

    Consider a single Zinc Copper electrode pair, the thing called a Daniel Cell.
    So it provides a PD of 1.08 volts.

    Now when i connect a 0.1 ohm resistor, what actually happens in the cell??

    Can anyone throw some light on this??
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,144
    1,791
    At the electron level any resistance will oppose the flow of current. You won't be able to get anywhere near the open circuit voltage on the 0.1 ohm resistor unles the internal resistance is very much less than 0.1 ohms.

    Electrical current also produces heat. Heat will raise the temperature of a material and most materials have a positive temperature ceofficient. This means that an increase in temperature will cause an increase in resistance.
     
  3. greenberet

    Thread Starter New Member

    Nov 13, 2006
    9
    0
    What i actually want to know is that once i short circuit a cell, can it be used again or its ampere-hour capacity will be finished
     
  4. richbrune

    Senior Member

    Oct 28, 2005
    106
    0
    different types of batteries respond differently to "short circuits"--which are really just very low resistance loads. Nicads do pretty well, but Lead-acid batteries can be damaged from the heat.
     
Loading...