wounderful slides

1. OPERATIONAL AMPLIFIER

2. OP-AMPLIFIER
• amplifier is an important electronic circuit that is
used in almost every electronic instrument.
• An amplifier is a device that accepts a varying input signal and produces a similar
output signal with a larger amplitude.
• The name “operational amplifier” comes from the fact that they were
originally used to perform mathematical operations such as integration
and differentiation.

3. AMPLIFIER FIG18.23 INSIDE
AMP

4. DIFFERENCE BETWEEN AMP &OP-AMPLIFIER
• An Operational Amplifier is basically a three-terminal device
which consists of two high impedance inputs, one called the
Inverting Input, marked with a negative or “minus” sign, ( – )
and the other one called the Non-inverting Input, marked with
a positive or “plus” sign ( + ).
• An operational amplifier (often op-amp or op amp) is a DC-
coupled high-gain electronic voltage amplifier with a
differential input and, usually, a single-ended output.

5. AMPLIFIER
An amplifier is a electronic device that is increase the voltage, current,
or power of a signal . Amplifiers are used in wireless communications
and broadcasting, and in audio equipment of all kinds. They can be
categorized as either weak-signal amplifiers or power amplifiers.
• An electronic device that is used to increase the magnitude of an electrical
signal.
• b. A device that is used to increase the magnitude of an information-carrying

6. CHARACTERISTICS OF OP-AMP
An op-amplifier has a large number of characteristics parameter
We will discuss three only .
• input Resistance
• Output Resistance
• Open loop Gain

7. INPUT RESISTANCE
• It is the resistance b/w the positive (+)and (-) inputs of the
amplifier.
• Its value is very high –of the order of several mega ohms.
• Due to high value of input resistance R practically no current
flows between the two input terminals.
• It is very important feature of op-amps.

8. OUTPUT RESISTANCE
• It is the resistance between the output terminated ground .
• Its value is only a few ohms.

9. OPEN LOOP GAIN
• It is the ratio of output voltage to the voltage diff b/w non-
inverting and inverting inputs when there is no external
connection between the output and inputs.
• The open loop gain of the amplifier is very high.
• It is of the order of 10.
• Mathematical Expressions
AOL =Vo /V+ -V- =V0 /Vi

10. INVERTING AMPLIFIER
• An inverting amplifier is a special case of the differential
amplifier in which that circuit's non-inverting input V2 is
grounded, and inverting input V1 is identified with Vin above.
The closed-loop gain is R2/ R1

11. MATHEMATICALEQN
• Current through R1=I1=vIN-v0/R1=vin-0/R1=-vin/R1
• Current through R2=I2=V--V0/R2=0-V0/R2=-v0/R2
• As practically no current flows between (-) and (+)
terminals,
• so by Kirchhoff’s current rule I1=I2
• Vin/R1=V0/R2
• V0/vIN=-R2/R1
• Gain=-R2/R1

12. NON-INVERTINGAMPLIFIER
• The second basic configuration of an operational amplifier
circuit is that of a Non-inverting Operational Amplifier.
• In this configuration, the input voltage signal, ( Vin ) is applied
directly to the non-inverting ( + ) input terminal which means
that the output gain of the amplifier becomes “Positive” in value
in contrast to the “Inverting Amplifier” circuit .

13. MATHEMATICAL EQN.
• v-~v+ = vin
• Current through R1=I1=0-vin/R1=0-vin/R1=-vin/R1
• Current through R2=I2=V—V0/R2=Vin-V0/R2
• As practically no current flows between (-) and (+) terminals, so
by Kirchhoff’s current rule I1=I2
• -Vin/R1=Vin-V0/R2
• Vin [1/R1+1/R2]=V0/R2
• Gain=V0/Vin=1+R2/R1

14. USES OF OP-AMPLIFIER
Operational amplifiers are widely used in signal processing
circuits and control circuits.
all analog integrated circuits, the operational amplifier is the
analog integrated circuit is the most widely uses circuits.

15. USE OF OP-AMPLIFIER
One op amp can take the place of as many as 20 discrete
electronic components.
These devices are used by electrical engineers as basic
compact components in the design of electronic devices and
appliances.

16. PRESENTED BY:
•MUHAMMAD YASIR
• TOQEER NASIR
• USMAN RAMZAN
• QADEER ABBAS
• MUHAMMAD SHAHID