Ohm Law

Ohms law, sometimes more correctly called Ohm's Law, named
after Mr. Georg Ohm, mathematician and physicist b. 1789 d. 1854 - Bavaria,
defines the relationship between power, voltage, current and resistance.

The principles apply to a.c., d.c. or r.f. (radio
frequency).

http://www.the12volt.com/ohm/page2.asp

http://www.electronics-tutorials.com/basics/ohms-law.htm

Ohm's Law defines the relationships between
(P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the
resistance value through which one volt will maintain a current of one ampere.




( I ) Current is what flows on a wire or conductor
like water flowing down a river.
Current flows from negative to positive on the surface of a conductor.
Current is measured in (A) amperes or amps.




( E ) Voltage is the difference in electrical potential
between two points in a circuit. It's the push or pressure behind current flow through a circuit,
and is measured in (V) volts.




( R ) Resistance determines how much current will
flow through a component.
Resistors are
used to control voltage and current levels. A very high resistance allows a small amount of current
to flow. A very low resistance allows a large amount of current to flow. Resistance is measured
in ohms.




( P ) Power is the amount of current times the voltage
level at a given point measured in wattage
or watts.



http://www.the12volt.com/ohm/ohmslaw.asp

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Direct links to other DC Electronics pages:
Fundamentals of Electricity:	[Introduction to DC Circuits] [What is Electricity?] [Electrons] [Static Electricity] [The Basic Circuit] [Using Schematic Diagrams] [Ohm's Law]
Basic Electronic Components and Circuits. . .
Resistors:	[Resistor Construction] [The Color Code] [Resistors in Series] [Resistors in Parallel] [The Voltage Divider] [Resistance Ratio Calculator] [Three-Terminal Resistor Configurations] [Delta<==>Wye Conversions] [The Wheatstone Bridge]
Capacitors:	[Capacitor Construction] [Reading Capacitor Values] [Capacitors in Series] [Capacitors in Parallel]
Inductors and Transformers:	[Inductor Construction] [Inductors in Series] [Inductors in Parallel] [Transformer Concepts]
Combining Different Components:	[Resistors With Capacitors] [Resistors With Inductors] [Capacitors With Inductors] [Resistors, Capacitors, and Inductors]

Ohm's Law

One thing we need to be able to do when we see a schematic circuit
diagram is to perform mathematical calculations to define the precise
behavior of the circuit. All information required to perform such
calculations should be included on the schematic diagram itself. That way
the information is all in one place, and any required detail can be
determined readily.

Consider the basic circuit shown to the right. We know immediately that
the battery voltage is 6 volts and that the resistor is rated at
1000.
Now, how can we determine how much current is flowing through this
circuit?

---

If you go back to The Basic
Circuit, you'll note that the relationship between voltage, current,
and resistance is given as E = I × R.
Using basic algebra we can also rewrite this as:

• R = E ÷ I


• I = E ÷ R

These three equations describe Ohm's Law, which defines this
relationship.

---

In the circuit shown above, we see that E = 6 volts and
R = 1000. To find the current flowing in this circuit, we must
select the equation that solves for I. Using that equation, we note
that:

I = E ÷ R

I = 6v ÷ 1000

I = 0.006 ampere (A) = 6 milliamperes (mA)

---

All calculations involving Ohm's Law are handled in exactly the same
way. If the circuit gets complex, the calculations must be tailored to
match. However, each calculation is still just this simple.

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