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Current. Batteries. Basic Circuit Elements. Current is a measure of the movement of charge. Current is defined as the amount of charge that passes through a surface in a given amount of time. The units of current are amps.
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Current Batteries Basic Circuit Elements
Current is defined as the amount of charge that passes through a surface in a given amount of time. The units of current are amps The direction of the current is opposite to the flow of electrons. It may be thought of as the flow of positive charge. Current always flows from higher potential to lower potential.
+ - - + V A battery uses chemical reactions to cause a potential difference between the terminals The maximum value of the potential difference of a battery is called its voltage In a circuit diagram we draw it like this
This is how an alkaline cell (AA battery) works. Zn + 2 OH- —> ZnO + H2O + 2 e- 2 MnO2 + H2O + 2 e- —>Mn2O3 + 2 OH- Cathode (MnO2) Anode (Zn) ZnO Mn2O3 OH- MnO2 Zn H2O OH- MnO2 Zn + 2MnO2 —> ZnO + Mn2O3 + 1.5 V
- + V Current is defined as the amount of charge that passes through a surface in a given amount of time The units of current are amps (A) The direction of current is opposite to the flow of electrons The current may be though of as the flow of positive charge Current always flows from higher potential to lower potential In other words, current flows from the positive terminal of the battery through the circuit to the negative terminal In a circuit diagram we draw it like this - + I
- + V R C L S The following circuit elements and their symbolic representation are the ones most commonly found in circuits. NameSymbolUnits V Battery Ω Resistor F Capacitor H Inductor Switch
Current Batteries Basic Circuit Elements