Electronics 2 presentation of Spring semester by Himel Himo.

1. Submitted By:
Md.Al Imran Bhuyan(143-
19-1616)
Md.Nazmul Hasan(143-19-
1611)
Sabuj Mandal(143-19-

2.  An operational amplifier in which the input signal is
applied to the ungrounded positive input terminal to
give a gain greater than unity and make the output
voltage change in phase with the input voltage.

3.  To start the design process, we must determine the
following requirements based on the intended
application:
 Voltage gain
 Frequency range
 Load resistance
 Maximum input voltage

4.  As an example of the design procedure, let us design a
non inverting amplifier with the following
characteristics:
1. Voltage gain 8
2. Frequency range DC to 5 kilohertz
3. Load resistance 27kilohms
4. Maximum input voltage 800 milli volts RMS
We know there some resistors and a input signal
and an output signal exist in an op amp.

5. Firstly we have to determine an initial value for R1
resistor.
Generally, neither resistor should be less than 1.0 Kilo
ohms nor more than 680 kilo ohms unless there is a
compelling reason for them to be so.
From this rule, we select R1 as 4.7 kilo ohms.
Now we have to determine the value of RF.
RF can be computed from the voltage gain
equation,

6. We know that the Gain of an Operational Amplifier
is,
For the present design example, we compute RF as
below :
Now we need to find out the Value of
Compensation Resistor (RB).

7. We know that,
Now we have to determine the Required Unity
Gain Frequency.

8. Now we have to determine the Minimum Supply
Voltages .
To find out this we have to first find out maximum
output voltage
For our example, the maximum output voltage will be

9. The minimum power supply voltage can be determined
by the equation below:
At last, we have to determine the Required Stew
Rate

10. Finally we find the operational amplifier like below :

11. Now we are going to show that how to solve a
mathematical problem of an non inverting operational
amplifier.
Here is an non inverting op amp figure below :

12. From that figure you may be asked to find out some
parameters of the op amp like below:
 Voltage gain
 Input impedance
 Input current requirement
 Maximum output voltage swing
 Slew-rate limiting frequency
 Maximum input voltage swing

13. Firstly we show here how to find out the Voltage Gain .
We know that for an non inverting op amp,
Voltage Gain,
Now for the circuit we find,

14. Finally we can express the voltage gain in decibel as
below :
Now we have to find out the Input Impedance.
We know that,
Where Rop is the value of input resistance
provided by the manufacturer and Av is
the open-loop voltage gain of the op amp.

15. So we find for the circuit,
Here we take gain Av= 200,000 because of the
open loop.
Now we have to determine the Input Current
Requirement.

16. By applying Ohm’s law we can write from the circuit,
For finding Maximum Output Voltage Swing,
We know that,

17. Now we find out the Slew-Rate Limiting Frequency .
We know that,
At last we have to find out the maximum input
voltage swing of the operational amplifier.

18. We know that,
So by this way we can calculate all the
important terms to solve the mathematical
problem of an non inverting operational
amplifier.