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OHM LAW

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OHM LAW Powered By Docstoc
					Forging new generations of engineers
  Ohm’s Law

                      
And now, a word from Mr. Ohm
   In the early 1800’s, Georg Ohm
defined the fundamental relationship
  between: Voltage (E), Current (I)
    and Resistance (R) in electric
               circuits.
His experiments represent the
beginning of circuit analysis.
    Today, the Ohm’s Law
formula is used by engineers…


 …when designing circuits.
   Because electricity is very
predictable, circuit performance
     can be analyzed with
mathematical formulas such as
 Ohm’s Law before the circuits
     are even constructed!
Ohm’s Law
expresses the

                     E
relationship
between
Voltage (E),
Current (I),

                 I       R
and
Resistance (R)
in circuits.
                         E=IxR
  When any
  two of the
 Ohm’s Law                   E?
                             Voltage
   variables
 are known,
                     ?                 ?
                       I         R
   the third
    can be         Current      Resistance
  calculated
mathematically.

                  R=E/I        I =E / R
 In this lab activity, Ohm’s
Law will be investigated by
assembling two circuits. The
 The test results will then be
                          and
  circuits will be tested Law
 verified using Ohm’s
   Resistance, Voltage, and
         calculations.
 Current will be measured.
When making circuit measurements, it is
    The to always Units are…
importantEquivalentwork in Equivalent
               Units.




 K                V             mA
The following slides illustrate
 the correct way to make test
 measurements in the Ohm’s
      Law Lab activity.
  Series Circuit
Resistance Measurement
Start at 2K and adjust to higher range as necessary.




        Reading must be expressed in K
        Series Circuit
      Voltage Measurement




Meter is connected in Parallel with Circuit
  Set meter range to 20 Volts




Reading must be expressed in    V
       Series Circuit
     Current Measurement




Meter is connected in Series with Circuit
Start at 200 mA and adjust to lower range as necessary.




            Reading must be expressed in mA
  Parallel Circuit
Resistance Measurement
Start at 2K and adjust to higher range as necessary.




        Reading must be expressed in K
          Parallel Circuit
         Voltage Measurement




Meter is connected in Parallel with Circuit
  Set meter range to 20 Volts




Reading must be expressed in    V
          Parallel Circuit
         Current Measurement




Meter is connected in Series with Circuit
Start at 200 mA and adjust to lower range as necessary.




            Reading must be expressed in   mA
With test data inserted to the right of the equal
sign, you will solve Ohm’s Law equation for…

           V                                         V

          mA                                     mA

                                                    




… and last, but not least, don’t forget to try the
 Challenge Problem
The End

				
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