After reading this post you will learn about the basics of the Operational Amplifier, how the ideal characteristics of the op-amp differ from that of the practical one and what affect it have on the operation of the circuits. So sot back, keep reading and enjoy learning.
Introduction to Operational Amplifier:
Operational amplifier is one of the most popular electronic components in the analog electronics as it finds applications in a variety of circuits. An operational amplifier as the name implies can be used as signal amplifier, it can also be used in the active filters. Operational Amplifier is also very commonly used in front ends of the Data Acquisition Systems in the form of Instrumentation Amplifier, it also servers the important task in the Data Processing Systems. Operational Amplifier also finds application in test equipment, it can also found in the Signal Conditioning Circuits as wells as in the applications including the Instrumentation and the list go on. You must have figured out that Operational Amplifier is used in almost every discipline of the Analog Electronic besides these the concepts learned for the Operational Amplifier can also be applied for the Mixed Signal Circuitry where you need to Multiplex the analog sensors in order to record the data digitally. In short in order to survive in the vast field of electronics one should have the sound knowledge of the Operational Amplifier, must have the insight into the applications of the Operational Amplifier and understand the concept that lies behind the working of the Operational Amplifier. In this post I will try to give you the practical perspective of the Operational Amplifier and the posts that follows will discuss the nitty-gritty of the Operational Amplifier.
What is Op-Amp?
In the previous section you have learned the importance of Operational Amplifier and the very fields which employ the Operational Amplifier in some way. Let us now see what is the Operational Amplifier. Before diving deep into the discussion note here that the name of our component is composed of two words “OPERATIONAL” and “AMPLIFIER”. It is understood that the word AMPLIFIER implies that our device will amplify the signal at its input and the word OPERATIONAL here implies the diversity of the device that is by altering the feedback configuration of the device we can use it to perform various operations. So the operational amplifier means an amplifier that is capable of performing various Operations. We will see in the next pots that by how altering the feedback configuration determines the Operations of the Operational Amplifier. Here we will stick to the basics of the op-amp short for operational amplifier. The symbol of the Operational amplifier is shown in the figure below;
op amp 741 ic pin diagram:
The above picture shows the symbol of the Operational Amplifier that is used in the Schematics.as can be seen that Operational Amplifier utilizes two power supplies although there are other versions of the Operational Amplifier that uses only one power supply. The detailed discussion on the single and dual power supply will be made in the next posts. Operational Amplifier is always used with the feedback configuration. The detailed discussion on the feedback configuration is out of the scope of this post but I will discuss it in detail in other posts.
Pinout of the Operational Amplifier:
As can be seen in the above diagram that the Operational Amplifier has five terminals. Two of the five terminals are dedicated for the power supplies that is one terminal for the positive power supply and other terminal for the negative power supply. If you are using the single power supply Operational Amplifier one of the power terminal will be for positive lead and other terminal will be grounded. In the operational Amplifier there are two input terminals, basically the Operational Amplifier is the differential input amplifier that is the Operational Amplifier amplifies the difference between the voltages of the two input terminals. One input terminal is called the Inverting Input as it make the signal 180 degree out of phase at the output and the other input terminal is called the Non-Inverting input as it passes the signal without any phase change and of course the last pin is the output. It is important to note here that the Operational Amplifier has no ground terminal and the common ground of the two power supplies will act as the reference for the Output voltage. Another important thing to note here is that some operational amplifier has additional terminals for example the input offset terminal is present in some of the operational amplifiers with the help of which we can adjust the offset at the output.
Operational Amplifier IC Package:
Operational Amplifier usually comes in the DIP package with two, four and eight operational amplifiers in the single chip. One of the most commonly used IC of the op-amp is 741. Although it does not meet the ideal characteristics of operational amplifier but still it is the best starting point for the students new in the field as it is cheap and easily available in the market. Below is the pinout of the 741 IC.
Operational amplifiers also come in other part number we will discuss them in detail in next posts.
Ideal Characteristics of the Operational Amplifier:
Let us now see what are the ideal attributes of the Operational Amplifier. These are the attributes that a good operational amplifier should meet but obviously the practical Operational Amplifier has some deficiencies regarding these attributes. Some important ideal characteristics of the Operational Amplifier are listed below:
- Infinite input impedance.
- Zero output impedance.
- Infinite gain.
We will see in the next post what are advantages of having the infinite input impedance and zero output impedance.
It is important to note here that the Operational Amplifier acts as the ideal voltage source as it has zero output impedance.
Some of the common configurations of the Operational Amplifier:
The most common configurations of the Operational Amplifier are:
- Inverting Operational Amplifier.
- Non-Operational Amplifier.
As the name implies the inverting Operational Amplifier will shift the phase of its input signal by 180 degrees. The circuit for the Inverting Amplifier is shown below:
As it is clear that the non-inverting operational amplifier passes the input signal as it is but just amplifying it. The normal circuit for Non-inverting Operational Amplifier is shown in the figure;
That is all for now I hope this article would be helpful for you. In next article I will discuss in detail the working of the inverting and non-inverting operational amplifier. Till then stay connected keep reading and enjoy learning.
op amp input bias current and offset current:
Operational Amplifier as Differential Amplifier
Introduction to Operational Amplifier
Characteristics of the Ideal Operational Amplifier
Operational Amplifier as the Instrumentation Amplifier
Op amp inverting non inverting amplifier
we will learn Introduction to Operational Amplifier, Non-Inverting Amplifier and Inverting Amplifier. and discues about what is op amp 741