Wien Bridge Oscillator


  • The function of the Wien bridge oscillator is to generator sinusoidal frequency. 
  • It is audio frequency oscillator.

Circuit Connection Diagram

  • The Wien bridge circuit is connected between amplifier input and output terminal. 


Inductor & Inductance


  • If several number of turns are wound over the core, it is generally called as Inductor. 

  • There are no power loss in the pure inductor. 
  • The core of magnetic material has negligible loop area is used in order to make inductor. 


Band Reject Filter OR Band Elimination Filter


Band Reject Filter ( Band Elimination Filter ) ( Band Stop Filter )

  • It is a filter in which frequencies below lower cut off frequencies and above higher cut off frequencies are passes whereas stop band frequencies are attenuated.

Range of frequencies

f < fL

fL < f < fH

f > fH

Allowed to pass

Not allowed to pass

Allowed to pass



Band Pass Filter

  • The band pass filter allows frequencies to be passed between lower cut off frequency ( fL ) and higher cut off frequency ( fH ) whereas it reject all other frequencies below fL and above fH.


fL = Lower cut off frequency

fH = Higher cut off frequency


High Pass Butterworth Filter

 First order High Pass Butterworth Filter

  • The high pass filter is obtained by changing frequency determining component – resistors and capacitors in the low pass filter. 
  • The first order high pass filter is obtained by interchanging R and C in the first order low pass filter. 
  • Figure shows first order high pass Butterworth filter.


Low Pass Butterworth Filter


First order Low Pass Butterworth Filter

  • It is a filter which has nearly ideal response, flat passband as well as flat stop band. 
  • As both passband and stop band are flat, it is also called as flat – flat filter.


Types of Filter


  • An electronics filter is a circuit which allows specific band of frequencies whereas blocks frequencies outside of the band.

Classification of Filter