Tutorial I
Chapter 1. Operational Amplifier Characteristics
1. An inverting amp is made using R2/R1 = 500. The input signal is VS =
(10mV)sinωt. The offset voltage for the op amp is 5 mV. What is the expected
output voltage?
2. For a non-inverting amplifier using op-amp having R1 = 10kΩ and Rf = 100
kΩ, evaluate the maximum output offset voltage due to Vio and IB. The op-amp
parameters have the following values:
Vio = 10 mV, IB = 300 nA and Iio = 50 nA
3. For the amplifier in question 2, determine:
a. Value of bias compensating/minimising resistor ROM.
b. The total output offset voltage Voo with ROM.
4. Evaluate the values of the two input bias currents IB+ and IB- if the values of
the input offset current and input bias current are 10nA and 50nA
respectively.
5. An op amp has listed slew rate of 1 V/µs. In trying to amplify a sine wave with
output amplitude of 3 V, what is the highest frequency that can be used
without distortion?
6. Determine the maximum frequency for an input a.c. signal of 0.02 V peak that
may be amplified without any distortion using an op-amp with slew rate SR
= 0.5 V/µs and closed-loop voltage gain of 24.
7. An op-amp has a slew rate of 2 V/µs. Determine the rise time for an output
voltage of 10 V amplitude resulting from a rectangular pulse input if the op-
amp is slew rate limited.
8. In a closed-loop inverting configuration of an op-amp, the input resistance
and the feedback resistance are 1 KΩ and 33 KΩ respectively. (i) Determine,
the value of VP, for an undistorted output if an input to the current is Vin = VP
sin(2πft), where f = 1 kHz and slew rate = 0.6 V/μs. (ii) lf the value of VP is
assumed to be 5V, state two possible remedies in the circuit to have an
undistorted output.
9. A 741 op-amp with slew rate SR = 0.5 V/μs is used as part of a motor control
system. If the highest reproducible frequency is 3 kHz and the maximum
output level is 12 V peak, does slewing ever occur?
Tutorial I
Chapter 1. Operational Amplifier Characteristics
10. In a closed-loop inverting configuration of an op-amp with a slew rate of 0.5
V/μs, the input resistance and the feedback resistance are 1 KΩ and 330 KΩ
respectively. The input signals are as follows:
V1 = 0.01sin l06t V
V2 = 0.005 sin (350 x 103)t V
V3 = 0.l sin (200 x 103)t V
V4 = 0.l sin (50 x 103)t V
Determine whether the output will get distorted due to slew rate limitation?
Find the new value of feedback resistor such that none of the signal gets
distorted.
11. An op-amp with a differential gain of Ad = 4000 is supplied with input
voltages of Vi1 = 150 µV and Vi2 = 140 µV. Determine the output voltage if the
value of CMRR is: (a) 100 (b) 105.
12. The input terminals of an op-amp are connected to voltage signals of strength
745 μV and 740 μV respectively. The gain of the op-amp in differential mode
is 5x105 and its CMRR is 80 dB. Calculate the output voltage and percentage
error due to common mode.
