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D.C. Theory
© copyright
M.J.Morris 2004

2.06 Voltage Drop.

There are two types of potential difference.

1. An electro-motive force (e.m.f.).

   
   An e.m.f increases the electrical potential of the electrons. e.g. The voltage across a battery, is due to the e.m.f. increasing the potential of the electrons, as it transfers them between its terminals. The electrons leaving the negative terminal, have a higher potential than the electrons arriving at the positive terminal.
   
   

2. A potential drop (p.d.) (or voltage drop (v.d.)).

   
   A voltage drop occurs across a component that reduces the electrical potential of the electrons as they pass through it. e.g. A resistor converts electrical energy to heat and therefore lowers the potential of the electrons passing through it. A voltage drop occurs across a resistor, because the electrons flowing out of the resistor, have a lower potential than those flowing into it.