Instrumentation amplifier objective questions test
Answer: In order to maximize dynamic range in precision sensor measurements, it may be necessary to use a programmable gain instrumentation amplifier PGIA. Because most instrumentation amplifiers in-amps use an external gain resistor RG to set the gain, it would seem the desired programmed gains can be achieved with a set of multiplexed gain resistors. While this is possible, there are three major issues to consider before implementing a system this way with a solid-state multiplexer: supply and signal voltage limitations, switch capacitance, and on resistance. Figure 1. When the source or drain voltage exceeds the supply, fault current can flow and cause an incorrect output.
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- Electronic Devices - Special-Purpose Op-Amp Circuits
- Operational Amplifier Question & Answers
- Smart, Connected, Secure Solutions for ADAS Applications
- What is the purpose of using a differential amplifier? (Common-mode rejection ratio: CMRR)
- Multiple choice questions - raisoni
- Which of the following cannot be treated as a requirement of the instrumentation amplifier?
- objective question of instrumentation branch with answers quarry ridge apartments
Electronic Devices - Special-Purpose Op-Amp Circuits
In this tutorial, we will learn about few important Instrumentation Amplifier Basics and Applications and also the circuit and working of a three Op-amp Instrumentation Amplifier. Many industrial and consumer applications require the measurement and control of physical conditions.
For example, measurements of temperature and humidity inside a diary plant to accurately maintain product quality, or precise control of the temperature of a plastic furnace to produce a particular grade of plastic, etc. These changes in physical conditions must be converted to electrical quantities using transducers, and then amplified.
Such amplifiers, which are used to amplify signals to measure physical quantities are commonly known as Instrumentation Amplifiers. The input to an instrumentation amplifier is the output signal from the transducer. A transducer is a device which converts one form of energy into another. Most of the transducer outputs are of very low-level signals. Hence, before the next stage, it is necessary to amplify the level of the signal, rejecting noise and the interference.
The general single ended amplifiers are not suitable for such operations. For the rejection of noise, amplifiers must have high common-mode rejection ratio. The special amplifier which is used for such low-level amplification with high CMRR, high input impedance to avoid loading is an Instrumentation Amplifier. The instrumentation amplifier is intended for precise, low-level signal amplification where high input resistance, low noise and accurate closed-loop gain is required.
Also, low power consumption, high slew rate and high common-mode rejection ratio are desirable for good performance. An instrumentation amplifier is usually employed to amplify low-level signals, rejecting noise and interference signals. Therefore, a good instrumentation amplifier has to meet the following specifications:. Finite, Accurate and Stable Gain: Since the instrumentation amplifiers are required to amplify very low-level signals from the transducer device, high and finite gain is the basic requirement.
The gain also needs to be accurate and the closed-loop gain must be stable. Easier Gain Adjustment: Apart from a finite and stable gain, variation in the gain factor over a prescribed range of values is also necessary. The gain adjustment must be easier and precise. High Input Impedance: To avoid the loading of input sources, the input impedance of the instrumentation amplifier must be very high ideally infinite. Low Output Impedance: The output impedance of a good instrumentation amplifier must be very low ideally zero , to avoid loading effect on the immediate next stage.
High CMRR: The output from the transducer usually contains common mode signals, when transmitted over long wires. A good instrumentation amplifier must amplify only the differential input, completely rejecting common mode inputs. Thus, the CMRR of the instrumentation amplifier must be ideally infinite. High Slew Rate: The slew rate of the instrumentation amplifier must be as high as possible to provide maximum undistorted output voltage swing.
The most commonly used Instrumentation amplifiers consist of three op-amps. In this circuit, a non-inverting amplifier is connected to each input of the differential amplifier. This instrumentation amplifier provides high input impedance for exact measurement of input data from transducers. The circuit diagram of an instrumentation amplifier is as shown in the figure below. The op-amp 3 is a difference amplifier that forms the output stage of the instrumentation amplifier.
The output stage of the instrumentation amplifier is a difference amplifier, whose output V out is the amplified difference of the input signals applied to its input terminals. If the outputs of op-amp 1 and op-amp 2 are V o1 and V o2 respectively, then the output of the difference amplifier is given by,. The expressions for Vo1 and Vo2 can be found in terms of the input voltages and resistances. Consider the input stage of the instrumentation amplifier as shown in the figure below.
The potential at node A is the input voltage V 1. Hence the potential at node B is also V 1 , from the virtual short concept. Thus, the potential at node G is also V 1. The potential at node D is the input voltage V 2.
Hence the potential at node C is also V 2 , from the virtual short. Thus, the potential at node H is also V 2. Ideally the current to the input stage op-amps is zero. Therefore the current I through the resistors R 1 , R gain and R 1 remains the same. The output of the difference amplifier is given as,.
Substituting V o1 — V o2 value in the equation 3, we get. The above equation gives the output voltage of an instrumentation amplifier. The resistive transducer bridge is a network of resistors whose resistance varies due to changes in some physical condition.
For example, Thermistors change their resistance with temperature and Light Dependent Resistors change their resistance to change in light intensity. By making such a bridge as a part of the circuit, it is possible to produce an electrical signal proportional to the change in the physical quantity being measured. Such an electrical signal can be amplified and used to monitor and control the physical process.
An instrumentation amplifier can be constructed with a transducer bridge connected to one of its input terminals, as shown in the figure below. The resistive bridge is supplied with a DC voltage, V dc. When the bridge is balanced, i. Under this condition, the differential input to the instrumentation amplifier is. Thus, the output of the amplifier is zero.
Consequently, the display device connected at the output displays the reference value of the physical quantity being measured. The reference condition is generally chosen by the designer and it depends on the device characteristics of the transducer, the type of physical quantity being measured and the type of the application. When there is a change in the physical quantity being measured, the voltage V a will no longer be equal to V b.
This produces a differential input for the instrumentation amplifier and the output of the amplifier will no longer be zero. But the voltage V a changes due to the change in resistance of the transducer device and is now given as,. The differential voltage V Diff is,. If all the resistances in the circuit are chosen to be of same value, i.
If the value of V Diff is positive, it indicates that V b is greater than V a. The display can be calibrated in terms of the units of the physical quantity being measured. The instrumentation amplifier, along with a transducer bridge can be used in a wide variety of applications. These applications are generally known as data acquisition systems. At the input stage, there is a transducer device that converts the change in the physical quantity to an electrical signal. The electrical signal is fed to an instrumentation amplifier.
The amplified signal is then fed to a display device, which is calibrated to detect the change in the quantity being measured. A simple temperature controller system can be constructed using a thermistor as the transducer device, in the resistive bridge, as shown in the figure above. The resistive bridge is kept balanced for some reference temperature. The circuit shown for temperature controller can also be used as a temperature indicator. The temperature indicating meter is calibrated to reference temperature, corresponding to this reference condition.
As temperature changes, the amplifier output also changes. The gain of the amplifier can be appropriately set to indicate the desired range of temperature.
The same circuit can be used to detect variations in the intensity of light, by replacing the thermistor by a Light Dependent Resistor LDR. The bridge is set to a balanced condition in darkness. When light falls on the LDR, its resistance changes and unbalances the bridge. This causes the amplifier to produce a finite output, which in turn drives the meter. Previous — Differential Amplifier.
Next — Op Amp as Integrator. I think slew rate should be low , so that output of an opamp can reach to its max value in least time.. Your email address will not be published.
Instrumentation Amplifier Basics and Applications. January 31, By Administrator. Was very helpful. Leave a Reply Cancel reply Your email address will not be published.
Operational Amplifier Question & Answers
Instrumentation Amplifier In-Amp forms the basic component of every measuring instrument and testing equipment. Instrumentation Amplifier is available in integrated circuit form and can also be built using Op-amps and Resistors which have very low tolerance value called as Precision Resistors. This post will provide you a better understanding about what is Instrumentation Amplifier, its Working Principle, Applications, Advantages and Disadvantages. Instrumentation Amplifiers are basically used to amplify small differential signals.
Smart, Connected, Secure Solutions for ADAS Applications
There are 9 questions to be attended in 20 minutes. The questions are on Measurement and Instrumentation. The study material is provided along with the remarks for each answer after you complete the examination to help building knowledge on the subject. There are 9 question banks of 9 question each and you should attempt each of these question bank to test your preparedness for the final day of the RRB examination for SSE and JE to be held in Dec. Read the study material before making an attempt so that you build your confidence in the subject. You have reached 0 of 0 points, 0. The gain of amplifier is.
What is the purpose of using a differential amplifier? (Common-mode rejection ratio: CMRR)
Thank you. Recent Articles What is notepad in computer? What is responsive web design and why is it important? The node voltage at the top of the til resistor is closes to zero. What is the another name for a unity gain amplifier?
Multiple choice questions - raisoni
Instrumentation Engineering Questions and Answers - Sanfoundry. Top Instrumentation Engineering Objective Questions. EBooks Multiple Choice Questions Answer Instrumentation Engineering If you ally need such a referred multiple choice questions answer instrumentation engineering ebook that will pay for you worth, get the completely best seller from us currently from several preferred authors. Consider the entire resistors in the bridge circuit are equal. Top Instrumentation engineering multiple choice questions Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website.
Which of the following cannot be treated as a requirement of the instrumentation amplifier?
If you have a little experience about the application of differential amplifier then you can easily understand the purpose of OP Amplifier. Operational Amplifier is a voltage amplifying device extensively used for mathematical operations such as add, subtract, integration and differentiation. It has 2 inputs and out output including feedback. The name of OP AMP used because of Mathematical Operations just like addition, subtraction, multiplication, differentiation and integration. Operational Amplifier can be used comparator, integrator, differentiator, Summer.
objective question of instrumentation branch with answers quarry ridge apartments
A differential amplifier amplifies the between two input signals. The differential amplifier can amplify ac as well as dc signals because it employs Noise of input signal in differential amplifier a increases b decreases c remains the soul 4.
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This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up their fundamentals on the Operational Amplifier topic. An operational amplifier also called OP-Amp and is a basic building block of analog-type electronic circuits. IC is an op-amp invented by Karl D in The output obtained from an op-amp is an amplified value of the input signal. There are 4 types of gain in op-amps namely, voltage gain, current gain, transconductance gain, and trans resistance gain.
In this tutorial, we will learn about few important Instrumentation Amplifier Basics and Applications and also the circuit and working of a three Op-amp Instrumentation Amplifier. Many industrial and consumer applications require the measurement and control of physical conditions. For example, measurements of temperature and humidity inside a diary plant to accurately maintain product quality, or precise control of the temperature of a plastic furnace to produce a particular grade of plastic, etc. These changes in physical conditions must be converted to electrical quantities using transducers, and then amplified.
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