1. Luigi Galvani (1737-1798) “Animal electricity”

2. Galvanic Cells Alessandro Volta showed that chemical reactions between metal electrodes and an electrolytic fluid can induce electrical current.

3. Voltaic Piles and Batteries Reactions in some batteries can be reversed to recharge the battery. Dry cell batteries – “safe” and “portable”

4. Batteries and Electrical Current Electrical current –Flow of charged particles –Symbol: I –Units: Coulombs/second (C/s) Voltage –the difference in electrical charge between two points in a circuit (electrical “pressure”) –Symbol: V –Units: volts (V) Battery –Converts chemical energy to kinetic energy (energy of flowing charges)

5. Electric Circuits Electric circuit –Unbroken path of material carrying electricity –Electrical conductor Circuit components 1. Source 2. Closed path 3. Device to use electrical energy Ohm’s Law –Current is directly proportional to voltage V and inversely proportional to resistance R –In symbols: I = V / R Electric Power: P = I × V

6. Two Kinds of Electric Circuits