7.1 Name THREE applications of an operational amplifier (op amp) - NSC Electrical Technology Power Systems - Question 7 - 2017 - Paper 1
Question 7
7.1 Name THREE applications of an operational amplifier (op amp).
7.2 List THREE characteristics of an ideal operational amplifier (op amp).
7.3 Describe the term ... show full transcript
Worked Solution & Example Answer:7.1 Name THREE applications of an operational amplifier (op amp) - NSC Electrical Technology Power Systems - Question 7 - 2017 - Paper 1
Step 1
Name THREE applications of an operational amplifier (op amp).
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Linear amplifiers
Pulse amplifiers
Differentiating amplifiers
Step 2
List THREE characteristics of an ideal operational amplifier (op amp).
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Input draws no current.
The open-loop voltage gain is infinite.
Output impedance is zero; input impedance is infinite.
Step 3
Describe the term open loop with reference to an operational amplifier (op-amp).
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Open loop means that there is no feedback from the output back to the input. Consequently, the gain of the circuit is at a maximum.
Step 4
Draw the diagram of an operational amplifier (op amp) as an inverting voltage comparator.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Refer to the provided figure for the operational amplifier circuit diagram.
Step 5
Explain the term positive feedback.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In positive feedback, a portion of the output signal is fed back to the inverting input and is in phase with the input signal, which increases the output further.
Step 6
Explain what effect the very high input impedance (close to infinity) of an op amp will have on the preceding circuit (circuit connected to input of the op amp).
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The very high input impedance will minimize the loading effect on the previous circuit. No current will be drawn from that circuit, hence the voltage will be transferred effectively.
Step 7
Give THREE applications of RC phase shift.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Audio oscillators
Electronic organs
GPS units
Step 8
With the given input signal at the non-inverting input, draw both the input and output signals on the same axis.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The signal waveforms should be plotted indicating the non-inverting nature and the output corresponding to the input, which should be a phase-shifted version.
Step 9
Explain the function of R in the circuit.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The resistor R allows for control of the op-amp circuit gain by feeding part of the output back to the inverting input.
Step 10
Explain what will occur to the gain of the operational amplifier (op-amp) if the value of R is decreased.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
If R is decreased, the feedback will increase, which will consequently increase the overall gain of the circuit.
Step 11
What is the function of R in the circuit?
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The function of R is to provide feedback that stabilizes the gain of the operational amplifier.
Step 12
Draw the circuit diagram of a Hartley oscillator.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Refer to the Hartley oscillator circuit diagram showing the relationship between the inductors and the amplifier.
Step 13
A comparator circuit compares two electrical signals. State, with a reason, the nature of the output if both signals have exactly the same value.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The output of the comparator will be zero, as the comparator only amplifies the difference between the two signals.
Step 14
In the amplification process, the amplitude of the wave form changes, what is the effect on the frequency?
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The frequency of the waveform remains unchanged during amplification.
Step 15
Explain the term natural oscillation frequency and draw THREE complete cycles to demonstrate natural oscillation frequency.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The natural oscillation frequency is the frequency at which the system oscillates in the absence of any driving influence. Three complete cycles should be drawn to illustrate this point.
Step 16
State, with a reason, the application that would require an op-amp to be used.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Operational amplifiers are used in situations like buffering between stages to adapt the impedance levels appropriately.
Step 17
When you use a non-inverting amplifier? Give ONE example to illustrate your answer.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A non-inverting amplifier is used when a signal needs to be amplified without inverting. An example could be audio equipment where maintaining phase is crucial.
