OBJECTIVES OF THIS SITE:

• Students will be able to understand the concept of Ohm's Law.
• Students will be able to identify real-life applications of Ohm's Law.
• Students will be able to understand the formulas, units, and variables related to Ohm's Law.
• Students will be able to solve problems involving Ohm's Law.

 

 
 
 
 
 



http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Ohm.html
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

• Georg Simon Ohm (1789-1854)

• The greater the battery voltage, the larger the current.
• The current is directly proportional to the voltage. For example, a 12 Volt battery would produce twice as much current as a 6 Volt battery, as long as each is connected to the same circuit.
• Resistance is defined as the ratio of the voltage used to the current produced through the circuit.                    (Resistance = Voltage/Current)
• This equation is referred to as Ohm's Law. It is named after the German physicist who discovered it, Georg Ohm.
• The SI Unit for resistance is called an ohm. It is represented by the capital Greek letter Omega.

• The main application of Ohm's Law is used when building electrical devices. Most appliances need a certain amount of voltage and current to operate. To figure out the most efficient way to get the proper current, Ohm's Law is used. Ohm's Law can tell you how much resistance you need to establish a certain current with a certain amount of voltage.
• Resistors are very important in electric circuits. They are used to limit the amount of current traveling through the circuit and to establish certain levels of voltage. Ohm's Law is used to figure out which resistors are needed.
• Without Ohm's Law, we wouldn't be able to figure out how much resistance is needed in a circuit, and therefore either too much or too little current or voltage would be produced.

 

 
 




Formulas




• Resistance is equal to Voltage divided by Current.
• The unit for resistance is an ohm, which is represented by the Greek capital letter Omega. (W)
• The unit for current is an ampere, also known as an amp. It is represented by a capital letter A. (A)
• The unit for voltage is a volt. It is represented by a capital letter V. (V)

The formula used to show Ohm's Law is W= V/A. A variation of this is Voltage is equal to Amps multiplied by Resistance, which is shown as V=AW.

Sample Problems

Sample Problem 1
  A circuit has 7 Volts going through it. The end result is 4.37 Amps being produced. Solve for the amount of resistance.

Solution
                    R= V  = 7 V    = 1.60 W
                       A    4.37 A
 

Sample Problem 2
  There are 3 Volts running through a circuit. The resistors in the circuit total 1750 Ohms. Solve for the Current.

Solution
                   A= V  =  3 V     =  .0017 A
                     W           1750 W
 

Sample Problem 3
 A circuit produces .0036 Amps. The resistance total is 16000 W. Solve for the total voltage.

Solution
               V= AW  = .0036A X 16000W =  57.6 V

Click here to see a page about resistors.
Click here to see a page about hybrid circuits.
Click here to see the main physics page.
Click here to see my page on kinematic equations.