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Flash link: 

https://vlab.amrita.edu/repo/PHY/HMW/BreadBoard_HartleyOscilator/BB_Hartley_oscilator.swf

 

PROCEDURE:

    

 1.  DESIGNING

 

   Selection of transistor: Use high frequency transistor BF195, NPN transistor.

     

             Component specification: I_C ( MAX) : 30mA                                   V_CEO ( MAX): 20V                                                                                                                                   β_MIN: 36                                                   β_MAX: 125

 

   Design of amplifier section

 

     dc bias conditions     

 

   Design of R_C  

 

     We know, then(use 4.7K std)

 

   Design of R_E  

 

  then

 

   Design of R₁ and R₂.

 

       Assume the current through and that through

           

          

       then (Select 10K std)

          

         Then      

 

   Selection of capacitors  :  All capacitor values may be taken 1μF

 

   Design of feedback network : Required frequency of oscillation

 

         We have Frequency of oscillation  ,where 

        so, 

       Let ,then  (1μH.std)

 

   2.  WORKING

 

The connections are made as shown in fig

The collector of the transistor is connected to the positive

of power supply (Vcc) through the resistance R_C.The

resistance R₁ and R₂ are connected in series with power

supply. The resistance R_E and the capacitor C_E are

connected in the emitter circuit. The negative terminal of

the power supply and emitter resistance R_E is earthed. An

inductance coil L connected parallel to the capacitor C

forms the tank circuit. The centre tap of coil L is earthed.

After making connections, the power supply is switched

on. The frequency of oscillations is measured using a

C.R.O.