Thursday, October 22, 2015

voltage divider

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 =Vin /(R1+R2)
So, voltage across the first resistor is
VR1 = I R1 = R1 Vin / (R1+R2)
                     
                        i.e,         VR1 = Vin  R1/(R1+R2)
Similarly, voltage across the second resistor would be

                                        VR2 = Vin 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.

  


Friday, September 11, 2015

what is electric current,voltage? a simple basic introduction for everyone to understand

Hey friends, if you find everything about electrical science difficult or hard to understand then you came to the write place and you are about to find it(electrical) pretty interesting.



                            So, first thing first what is electric current?
Before giving the answer to the above question let me tell you about a particle named Electron. Electron is a fundamental particle of Atom. Atom is made up of electrically charged particles, i.e. Electron, Proton and Neutron. Electron carries a unit negative(-) charge,Proton carries a unit positive (+) charge and Neutron is neutral i.e. it does not carry any charge.As electron is negatively charged it attracts proton which is positively charged and repel an electron, so we get the saying 'opposite attracts and same repels'. Now because of this attraction and repulsion particles exert a force on each other which helps them to move/accelerate in different directions. This exerted force by one particle on another is called Electromagnetic force, it occurs when Electromagnetic field comes in interaction with electrically charged particles.  Now electric current: " electric current is flow of electrical charge " and this flow of charge is carried by electrons from atom to another. As electrons are able to move from atom to atom , the atom that loses the electron becomes positively charged(because atoms are naturally neutral and if one loses a negative charge it become positively charged) and the atom that gains the electron becomes negatively charged(because of one excess electron), thus flow of electrons produced.Electric current is measured in amperes.
You can also see the video to understand current flow  in a wire.


As we know all matters are made up of atoms which have electric charges. Therefore they all carry electrical charges.The electrons which move from one atom to another are called free electrons. They only need some external force to move out of the orbit of that atom. Materials that have many numbers of free electrons are called conductors,materials that have moderate numbers of free electrons are called semi-conductor and materials which have number of free electrons almost equal to none are called insulators.

The external force required by the electron to move or the force required to make current flow through a conductor is called Voltage. Another term we used for voltage is potential. So during the flow of electrons the atom which loses electrons have more no of positive charges so it has higher potential and atoms which gains electron have more negative charges so it has lower potential. The difference between these two points is called potential difference.It is measured in volts.



Voltage is denoted by 'V'. Electric current is denoted by 'I'. The relation Between Electrical current and Voltage forms the very basic law of electricity i.e. ohm's law.
Which is given by,
                                                                   V=IR
i.e. "current through a conductor between two points is directly proportional to potential difference between two points".
R is the constant of proportionality, popularly known as resistance.
Now, what is resistance?
Resistance is that property of a conductor by virtue of which it(conductor) opposes the flow of current through it.

Resistance is the hindrance to the flow of charge. It is measured in ohms.