![]() In a galvanic cell, the positive ions carry the current through the cell and the electrons carry the current in the external circuit. In fact positive ions are also current carriers and they flow in the same direction as the current. This confusion arises because we tend to assume that electrons are the only current carriers. At this point the "equilibrium potential" is that which balances the difference between the propensity of the two metals to gain or lose electrons.Ĭurrent flows from the positive terminal to the negative terminal but confusingly, electrons flow in the opposite direction. A potential difference between the metals will therefore build up until it just balances the tendency of the electron transfer between the metals. When two dissimilar metals (or metal compounds) are put in contact or connected through a conducting medium there is a tendency for electrons to pass from the metal with the smaller affinity for electrons, which becomes positively charged, to the metal with the greater affinity which becomes negatively charged. The electrical (pump) pressure or potential difference between the + and - terminals is called voltage or electromotive force (EMF).ĭifferent metals have different affinities for electrons. The chemical reaction between the electrolyte and the positive (+) electrode inside the battery produces an excess of positive (+) ions (atoms that are missing electrons, thus with a net positive charge) at the positive (+) terminal - the cathode of the battery. The internal chemical reaction within the battery between the electrolyte and the negative metal electrode produces a build up of free electrons, each with a negative charge, at the battery's negative (-) terminal - the anode. In simple terms, energy cells or batteries can be considered as electron pumps. Note: The names "Batteries" and "Cells" are used interchangeably in this text though strictly speaking, a battery is made up from a group of energy cells. Woodbank does not monitor or record these emails
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