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Basic Electronics - Ohm's Law

Probably the most important law in electronics is Ohm's Law.

Ohms Law:  The voltage across a resistor equals the resistance of the resistor times the current flowing through it (V = R* I).

Ohm's law applies to electrical circuits; and in other words can be stated as "The current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them" 

Thus if you have a resistance (R) of 1000 ohms and a current (I) of 10 milliamps flowing through it, the voltage (V) over it will be: 1000 * 0.01=10V.

Ohms law can be expressed in the following ways:

V = R * I
R = V / I
I  = V / R
where V is the potential difference measured across the resistance in units of volts; I is the current through the resistance in units of amperes and R is the resistance of the conductor in units of ohms.

The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. He presented a slightly more complex equation than the one above to explain his experimental results. The above equation is the modern form of Ohm's law.

Ohm's law, in the form above, is an extremely useful equation in the field of electrical/electronic engineering because it describes how voltage, current and resistance are interrelated on a "macroscopic" level, that is, commonly, as circuit elements in an electrical circuit.

If you would like to read more about Ohm's Law, it's history and origin, visit Ohm's Law on Wikipedia for the details on this fundamental law of electronics.

Another person who has contributed a great deal to electronics is Gustav Kirchhoff. Gustav Kirchoff gave the famous Kirchhoff's Circuit laws.

 

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