1.
Pick all incorrect statements.
Ideal characteristics of Op-Amp are
A. Open loop gain is infinite.
B. Output Impedance is infinite.
C. Input Impedance is Zero.
D. Input Offset current is the algebraic difference between input currents.
Correct Answer
C. B and C
Explanation
The ideal characteristics of an Op-Amp are that its open loop gain is infinite (A), its output impedance is zero (B), its input impedance is infinite (C), and its input offset current is zero (D). Therefore, the incorrect statements are B and C, as the output impedance is not infinite and the input impedance is not zero.
2.
Find the gain of the inverting amplifier shown below.
Consider R1 = 40kΩ and RF = 400kΩ Assume op-amp is ideal.
Correct Answer
A. -10
Explanation
The gain of an inverting amplifier is determined by the ratio of the feedback resistor (RF) to the input resistor (R1), with the negative sign indicating an inverted output. In this case, the feedback resistor RF is 400kΩ and the input resistor R1 is 40kΩ. Therefore, the gain can be calculated as -RF/R1 = -400kΩ/40kΩ = -10. This means that the output voltage will be 10 times the input voltage, but with an opposite polarity.
3.
Open loop gain of an operational amplifier is
Correct Answer
D. Infinite
Explanation
The open loop gain of an operational amplifier is infinite. This means that the amplifier has very high gain and can amplify the input signal to a very large extent. The infinite open loop gain allows the operational amplifier to be used in various applications such as amplification, filtering, and signal conditioning. It is important to note that in practical applications, the open loop gain is not truly infinite, but it is very large and can be considered as infinite for most purposes.
4.
In the open loop configuration of OP-AMP _____________ feedback is used
Correct Answer
B. No
Explanation
The open loop configuration of an operational amplifier (OP-AMP) does not use any feedback. In this configuration, the output of the OP-AMP is not connected back to the input, which means there is no feedback path. Therefore, the correct answer is "no."
5.
In given circuit Vin = 4 V, R1 = 1KΩ and R2 = 10KΩ.What is the output voltage of an amplifier
Correct Answer
C. 44
Explanation
The output voltage of an amplifier can be calculated using the formula: Vout = Vin * (R2 / (R1 + R2)). In this case, Vin is given as 4V, R1 is 1KΩ, and R2 is 10KΩ. Plugging these values into the formula, we get Vout = 4 * (10K / (1K + 10K)) = 4 * (10K / 11K) = 4 * 0.909 = 3.64V. However, since the given options are not in decimal form, we need to round up the value. Therefore, the closest option is 44.
6.
For first order butterworth low pass filter, calculate cut off frequency if R=10kΩ and C = 0.001. Also calculate Avf if Rf = 100K Ω and R1 = 10kΩ.
Correct Answer
C. 15.915KHz,11
Explanation
The cutoff frequency of a first-order Butterworth low pass filter can be calculated using the formula:
fc = 1 / (2πRC)
Substituting the given values of R = 10kΩ and C = 0.001, we get:
fc = 1 / (2π * 10kΩ * 0.001) = 15.915KHz
The Avf (voltage gain) of the filter can be calculated using the formula:
Avf = -Rf / R1
Substituting the given values of Rf = 100kΩ and R1 = 10kΩ, we get:
Avf = -100kΩ / 10kΩ = -10
Therefore, the correct answer is 15.915KHz, -10.
7.
Output produce by an op-amp is in phase when input is applied to
Correct Answer
B. Non Inverting terminal
Explanation
When the input is applied to the non-inverting terminal of an op-amp, the output produced is in phase with the input. This is because the non-inverting terminal is connected directly to the input signal, while the inverting terminal is connected through a feedback resistor. As a result, the op-amp amplifies the input signal without changing its phase, leading to an output that is in phase with the input.
8.
Determine closed loop voltage gain of an non inverting amplifier if feedback resistor is double times input resistor
Correct Answer
A. 3
Explanation
The closed loop voltage gain of a non-inverting amplifier can be determined by dividing the feedback resistor by the input resistor. In this case, if the feedback resistor is double the value of the input resistor, the closed loop voltage gain would be 2. However, the given answer is 3, which is not consistent with the information provided. Therefore, the explanation for the given answer is not available.
9.
Inverting configuration adder can be used as
Correct Answer
D. All of three
Explanation
The inverting configuration adder can be used as a summing amplifier, averaging amplifier, and scaling amplifier. As a summing amplifier, it can add multiple input signals together. As an averaging amplifier, it can calculate the average of multiple input signals. And as a scaling amplifier, it can amplify or attenuate the input signals by a specific scaling factor. Therefore, it can perform all three functions effectively.