Ohm’s principal discovery was that the amount of electric current through a metal conductor in a circuit is directly proportional to the voltage impressed across it, for any given temperature. Ohm expressed his discovery in the form of a simple equation, describing how voltage, current, and resistance interrelate:
E=IR
In this algebraic expression, voltage (E) is equal to current (I) multiplied by resistance (R). Using algebra techniques, we can manipulate this equation into two variations, solving for I and for R, respectively:
I=E/R ; R=E/I
Analyzing Simple Circuits with Ohm’s Law
Let’s see how these equations might work to help us analyze simple circuits:
In the above circuit, there is only one source of voltage and only one source of resistance to current. This makes it very easy to apply Ohm’s Law. If we know the values of any two of the three quantities (voltage, current, and resistance) in this circuit, we can use Ohm’s Law to determine the third.
Creating android app for Ohm's law
Mobile screen:
Main page
Slider block for Voltage adjustment
Math block for Ohm's Law
Initialize Block for Input variables:
Slider block for resistance adjustment:
Ohm’s Law Applications
The main applications of Ohm’s law are:
To determine the voltage, resistance or current of an electric circuit.
Ohm’s law is used to maintain the desired voltage drop across the electronic components.
Ohm’s law is also used in dc ammeter and other dc shunts to divert the current.
Limitations of Ohm’s Law
Following are the limitations of Ohm’s law:
Ohm’s law is not applicable for unilateral electrical elements like diodes and transistors as they allow the current to flow through in one direction only.
For non-linear electrical elements with parameters like capacitance, resistance etc the voltage and current won’t be constant with respect to time making it difficult to use Ohm’s law.