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- เผยแพร่เมื่อ 20 ส.ค. 2024
- #MindsRiot #TunedAmplifier #Amplifier
Link to notes: tasks4you.blog...
Tuned amplifiers are needed to pickup and amplify the specific frequency while rejecting all other frequencies. General amplifiers are used to amplify overall frequencies where tuned amplifiers are used to select specified frequencies and for amplification. Following table gives difference between general amplifiers and tuned amplifiers. TV and radio operates in the frequency rage say 500 KHz to few hundred MHz which is divided in many small frequencies that are assigned to different TV and radio stations. We need to select the desired frequency i.e. station and amplify it in order to receive it. Tuned amplifier does the same.
In order to pick up and amplify the desired radio frequency signal, the resistive load in the audio amplifier is replaced by a tuned circuit (also called a parallel resonant circuit)as shown in the figure. The tuned circuit is capable of selecting as particular frequency and rejecting the others. Thus the use of tuned circuit in the transistor amplifier circuit, makes possible the selection and amplification of a particular desired radio frequency. Such an amplifier is called tuned voltage amplifier.
Thus an amplifier, which amplifies a specific frequency (or a narrow band frequencies), is
known as tuned amplifier. It is basically used for purposes like:
(i) Selection of desired radio frequency signal.
(ii) Amplification of the selected signal to a suitable voltage level.
(i) Resonant Frequency(Fr): It is a frequency at which the inductive reactance is equal to the
capacitive reactance i.e. XL=XC. Resonant frequency is calculated by formula
Fr = 1/(2π√LC)
Q Factor: The quality factor or Q factor is a measure of the performance of a coil, capacitor inductor in terms of its losses and resonator bandwidth. Higher value of Q-factor provides the higher degree of selectivity in expense of bandwidth i.e. Higher the Q-factor, Higher the selectivity, but smaller bandwidth. On the other hand lower value of Q-factor provides poor selectivity but bandwidth is larger.
Q = 2πFrL/R
or
Q = Fr/BW
Where ,
Fr = Resonant frequency
L = value of circuit inductance.
R = Value of circuit resistance.
(iii) Bandwidth: Bandwidth is measure of its satisfactory working range.
BW = Fr/Q
Where ,
Fr = Resonant frequency
Q = Quality factor
Good job sir
Keep it up sir
the explanation was very insightful. can you please share the problem statement of this circuit, it will be really helpful.
Very illustrative sir. 👍
Excellent expert
Many many thanks
Thank you, engineer. Is this circuit for wireless audio transmitter? I mean, this is a transmission circuit..
Tuned Amplifiers are used to select and amplify perticular frequency like in TV and radio receiver
@@MindsRiot Well, well .. if we put a reverse bias capacitor in this circuit between the collector and a meter and put our antennas in a transmission resonance circuit, it could become a transmitter circuit
Sir, how did u change the values of components plz tell me🙏🙏
Double click on component to change values, labels etc
or
right click on component and go into properties.
Sir am not getting the resonant freq like yours what should I do?
See proper connection and component values
Sir u have used capacitive coupling or bjt