Current: Difference between revisions
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== What is current? == | == What is current? == | ||
Simply, current is the flow of electric charge through a conductor. | |||
===Conventional Current=== | |||
The notion of conventional current was started by Bejamin Franklin who sought to decribe the phenomenon of static electricity saying that charge (electrons) could be "rubbed off" some materials by others. He proposed that charge was transferred from wax to wool when they are rubbed together. He described the wool as being "negative" or having a deficiency of charge which allowed the transfer to take place. These experiments occurred well before the nature of electrons was dicovered, by which time his descriptions had taken a firm hold in the scientific community. | |||
Hence, conventional current is said to flow from positive to negative. | |||
=== Electron Flow Current=== | |||
We now know that electrons carry an negative charge, and that similar charges repel. Hence, in an electic circuit, negative charge (and electrons) will move from the more negative end of the circuit to the more positive. | |||
===Does it matter which one we use?=== | |||
In simple circuis the answer is no. Many circuits however contain "polarised" components that only work properly if they are placed in the circuit in a particulat orientation. One example is the [[Diodes | diode]]. Polarised devices are usually [http://www.howstuffworks.com/diode.htm semiconductors] | |||
==How is current measured?== | ==How is current measured?== | ||
Revision as of 16:34, 24 October 2008
Related wiki pages: Voltage, Resistance
What is current?
Simply, current is the flow of electric charge through a conductor.
Conventional Current
The notion of conventional current was started by Bejamin Franklin who sought to decribe the phenomenon of static electricity saying that charge (electrons) could be "rubbed off" some materials by others. He proposed that charge was transferred from wax to wool when they are rubbed together. He described the wool as being "negative" or having a deficiency of charge which allowed the transfer to take place. These experiments occurred well before the nature of electrons was dicovered, by which time his descriptions had taken a firm hold in the scientific community.
Hence, conventional current is said to flow from positive to negative.
Electron Flow Current
We now know that electrons carry an negative charge, and that similar charges repel. Hence, in an electic circuit, negative charge (and electrons) will move from the more negative end of the circuit to the more positive.
Does it matter which one we use?
In simple circuis the answer is no. Many circuits however contain "polarised" components that only work properly if they are placed in the circuit in a particulat orientation. One example is the diode. Polarised devices are usually semiconductors
How is current measured?
External links: