In this post I will discuss some of the common applications of the Operational Amplifier(op amp). The Operational Amplifier can be configured to perform a variety of tasks and the tasks that the Operational Amplifier performs are determined by the feedback network of the Operational Amplifier configuration. I have discussed in my first post on the Operational Amplifier series the various departments of the electronics where the Operational Amplifier is used. Some of these fields which require Operational Amplifier are Data Acquisition Systems, Data Processing Systems, Signal Conditioning Circuits, test equipment designing, Instrumentation and many more. I am discussing these fields here to give you the perception of the diversity of the Operational Amplifier applications. But it is important to note here that the Operational Amplifier is used in the form of systems in these applications. The point I am trying to make is that in the fields described above the Operational Amplifier is used as unique configurations for example in Signal Conditioning the Operational Amplifier is used as the Buffer Amplifier, in the Data Acquisition Systems the Operation Amplifier is used as the Instrumentation Amplifier, in the filters the Operational Amplifier is used as the differential Amplifier which eliminates the common mode signals in the information signal so it is useful that we have the knowledge of these circuits. This post will describe some of the important circuit configurations that are commonly used in the field of Electronics.
After reading this post you will learn about the variety of circuits that can be designed using the Operational Amplifier, the transfer equation of each Operational Amplifier configuration. So sit back keep reading and enjoy learning.
Operational Amplifier Applications:
As the point I have made in the above discussion is about the variety of the Operational Amplifier configurations the following list shows some of the commonly known Operational Amplifier circuits:
- Instrumentation Amplifier
- Buffer Amplifier
- Inverting Amplifier
- Non-inverting Amplifier
- Differential Amplifier
- Transimpedance Amplifier
Here I will discuss these Operational Amplifier circuits.
Buffer Amplifier is also known as the voltage follower circuit as the output voltage of the Amplifier follows the input signal. The buffer amplifier is implemented by connecting inverting terminal of the Operational Amplifier to its output and the non-inverting terminal is connected at the signal source. So the configuration the results is the unity feedback configuration as the gain of the Buffer Amplifier is one and the signal is just replicated at the output of the Amplifier. a question that arise here is why do we use the Buffer Amplifier if we do not employ it to amplify the signal, so the answer to this question is Buffer Amplifier is basically intended to be used for impedance transformation so the signal source for example the thermocouple does not get loaded due to the circuit to which is connected. The Buffer Amplifier is shown in the figure below:
Instrumentation Amplifier is another important amplifier type that can be implemented using the Operational Amplifiers. I have already discussed the instrumentation Amplifier in my posts however the Instrumentation Amplifier is basically the Differential Amplifier with the Buffer Amplifiers connected to each of the input of the differential amplifier. This type of amplifier is used in the systems where we need to measure the signal via sensors. So the buffer amplifiers gibe amplification here in addition to the impedance transformation and then the differential amplifier removes the common mode signal from the differential signal which is usually the Electromagnetic Induction (EMI) noise. The instrumentation amplifier is shown in the image below:
Inverting Amplifier along with the Non-Inverting Amplifier is the most common and the simplest Operational Amplifier configurations. In the Inverting Amplifier the Non-Inverting Input terminal of the Operational Amplifier is grounded and the input signal is applied at the inverting input terminal with the resistive feedback configuration. The Inverting Amplifier as the name implies invert the input signal at the output. I have already discussed the Inverting Amplifier detail in my post. The Inverting Operational Amplifier is shown in the figure below:
As mentioned in the previous section that the Non-Inverting Amplifier is one of the most common and simplest implementation of the Operational Amplifier. In this Op-Amp configuration the inverting terminal of the Operational Amplifier is grounded and the input signal is connected to the Non-Inverting Input terminal. The output voltage of the Non-Inverting Amplifier is identical in phase to that of the input but amplified by the amplification factor which is determined by the resistive feedback network. The Non-Inverting Operational Amplifier is shown in the figure below:
The Differential Amplifier is very important among the Operational Amplifier configurations. Basically the Operational Amplifier is the differential amplifier as it amplifies the difference of the voltage between its input terminals so in order to achieve this operation with controlled gain the Differential Amplifier is used. Notice here that the differential amplifier is the inverting and non-inverting amplifier in one circuit. An important advantage of the differential amplifier is the removal of the common mode signal in the input differential circuit. And also this amplifier is also used to convert the differential signal into the single ended output signal. The basic Operational Amplifier Differential Amplifier configuration is shown in the image below:
The trnasimpedance operational amplifier is another operational amplifier configuration. This type of amplifier is used to convert the current input signal into output voltage signal. It finds applications in the circuits where the input is the current source for example the photodiode. The output of the photodiode is the current signal so in order to manipulate the signal using the controller this signal needs first be converted into the voltage signal and this can be done by the Transimpedance Amplifier. The basic circuit of the Trasnimpedance Amplifier is shown in the figure below:
That is all for now I hope this post will be helpful for you. In the coming posts I will come up with more interesting applications of the Operational Amplifier. Till then stay connected, keep reading and enjoy learning.