Transcript Cells & Batteries

Cells & Batteries
Cells & Batteries

A cell a device that converts chemical
energy into electrical energy.

A battery is two or more electric cells,
joined and used as a source of electric
current.
Where does electricity come from?

Generators are the most common source
of electricity
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Hydroelectric generators
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Coal fired generators

Oil fired generators
Hydroelectric generators
Voltage of Cells & Batteries
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A volt is the unit used to measure voltage
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The SI unit is V
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The more voltage a cell has, the more energy is
supplied to the electrons that leave the cell to
produce an electric current
Voltage of Cells & Batteries
Voltage in the Battery = Sum of Voltage in the
Cells in the Battery
Example:
A flashlight uses 2 D-size batteries with 1.5 V cells.
Voltage in the flashlight battery = 1.5 V + 1.5 V
=3V
Measuring Voltage
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A voltmeter is used to measure voltage
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It looks like a galvanometer, but
measures voltage not current.
Measuring Voltage
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To connect a voltmeter to a cell,
Connect the positive (+) to positive (+)
and
Connect the negative (-) to negative (-)
Types of Cells & Batteries
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All cells have two features in common:
1) Presence of two different metals in the cell
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The metals are called the electrodes
2) Separation of the metals by a solution
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The solution is called the electrolyte
Types of Cells & Batteries
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All batteries contain:
1)
Electrodes
 the metals
2)
An Electrolyte
 the solution
Diagram of Zinc-Carbon Cell
Resistance

A resistor is a device made of material
that offers resistance to the flow of
charges
Resistance

For a current to exist in a wire, the electrons
must move past the atoms within the wire.

The greater the resistance of a material, the
greater the amount of energy the electrons
give up as they pass through it.
Resistance