Current Flow
1 Electrical and electronic devices work because of an electric current.
What is an electric current?
An electric current is a flow of electric charge. The electric charge usually consists of negatively charged electrons. However, in semiconductors, there are also positive charge carriers called holes.
2 There are several methods that can be used to generate an electric current.
Write at least three ways an electron flow (or current) can be generated.
The following is a list of the most common ways to generate current:
- Magnetically—This includes the induction of electrons in a wire rotating within a magnetic field. An example of this would be generators turned by water, wind, or steam, or the fan belt in a car.
- Chemically—This involves the electrochemical generation of electrons by reactions between chemicals and electrodes (as in batteries).
- Photovoltaic generation of electrons—This occurs when light strikes semiconductor crystals (as in solar cells).
Less common methods to generate an electric current include the following:
- Thermal generation—This uses temperature differences between thermocouple junctions. Thermal generation is used in generators on spacecrafts that are fueled by radioactive material.
- Electrochemical reaction—This occurs between hydrogen, oxygen, and electrodes (fuel cells).
- Piezoelectrical—This involves mechanical deformation of piezoelectric substances. For example, piezoelectric material in the ...
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