Embed Size (px)
DESCRIPTION
Automatic gain control is used in many electronic devices. The average or peak output signal level is used to adjust the gain to a suitable level, by making the circuit to work satisfactorily with a greater range of input signal levels.
Citation preview
PROJECT NAME : Automatic gain control
VERSION : TINA-TI 9.0
DATE OF SUBMISSION : 16-12-2013
AUTHORS : Swaroopnath Nagatri (Email id - [email protected])
FACULTY : Azarathamma(Email id - [email protected])
OBJECTIVE:
The Voltage gain control is used to analyze the change in the gain of the amplifier by passing the different input values.
SPECIFICATION TABLE:
Sl.No Components Specifications
1 Operational Amplifier U2 TL082
2 Resistor R1 = 2kΩ, R2 = 0.66Ω
3 Capacitor C1 = 241.11nF
4 Multiplier U3, U2
CIRCUIT DIAGRAM:
Fig.1: Circuit diagram of Automatic gain control
Page | 1
J1
J2
J1
J2
-
++
U1 TL082
U1*U2
U2 100k
U1*U2
U3 100k
R1 2k
R2 660
Vref 3 C1 241.1n
V2 12
V3 12
+ VG1Vc
Vo
THEORY:
Automatic gain control is used in many electronic devices. The average or peak output signal level is used to adjust the gain to a suitable level, by making the circuit to work satisfactorily with a greater range of input signal levels.
DESIGN PARAMETERS:
βvsat=3, f=1Khz
β*12=3
β=0.25
τ=1ms
A=-R2/R1
Let R1=1khz
Then R2=0.25khz
F= 1/2πRC
C=1/2*π*0.25*103*1*103
C=0.636uF
TABULAR COLOUMN:
Sl.No Input voltage Output Voltage(peak to peak)
Control Voltage(peak to peak)
1 2 30.17 v 3.41
2 3 31.26 v 3.42
3 4 31,15 v 3.33
Page | 2
OUTPUT WAVEFORM:
Fig.2: Output waveform of Automatic gain control for Vref=4V.
ADVANTAGES:
They provide enough amplification for the weak signals and prevent strong signals from getting over amplified.
It allows a system to automatically adjust itself based on environmental changes
DISADVANTAGES:
APPLICATIONS:
It is used in street lights to monitor the amount of sunlight and use the results to turn themselves on or off.
They are commonly found with microphone circuit for recording the voice at optimum signal level.
Page | 3
CONCLUSION:
Hence from the output waveform I conclude that voltage-controlled amplifier is an electronic amplifier that varies its gain depending on a control voltage.
Page | 4
