voltage divider rule

Voltage Division Rule

  
   ·        Definition of voltage divider

   ·        Voltage division

   ·        Applications of voltage division

Voltage divider definition

       Voltage divider also known as potential divider is a passive linear circuit and is may be defined as a number of electrical resistances connected to a voltage source in series used to obtain a desired fraction of input voltage as output.

 It comes with taps at certain points to obtain a variable fraction of input voltage as output, frequently used to give power supplies to electronic devices.

Voltage division

  The distribution of input voltage among the different elements of the voltage divider is called voltage division.

                                            

   

For example, we know

I =V_in /(R₁+R₂)

So, voltage across the first resistor is

V_R1 = I R₁ = R₁ V_in / (R₁+R₂)

                     

                        i.e,         V_R1 = V_in  R1/(R1+R2)

Similarly, voltage across the second resistor would be

                                        V_R2 = V_in R2/(R1+R2)

                 [since, in series circuit current is same in both the resistances]

Therefore, to find the voltage over an individual resistance in series, take the total series voltage and multiply by the individual resistance over the total resistance. 

  

Applications of voltage divider

 Voltage dividers are used for scaling of voltage levels, biasing of electronic devices and measurement of voltages. A potentiometer is a most common voltage divider which is used as a variable voltage divider in many radios to control the volume of radios.

                              

                                                                        Potentiometer                                  

There are other applications of voltage divider listed below,

   ·        By scaling down high voltages with the help of voltage divider, we can be able to  measure high voltages by voltmeter.

   ·        Voltage divider can be used to measure the resistance of sensors using microcontroller.