Understanding Source Transformations in Operational Amplifier Circuits

In summary, a student is asking for clarification on a step-by-step solution for a circuit analysis problem. They are confused about the final voltage in the simplified circuit and the calculation for it. They also ask about the meaning of "Rf" in the problem. Another user confirms that the calculation in the solution is incorrect and explains the meaning of "Rf" as the feedback resistor in the op-amp circuit.
  • #1
dwn
165
2

Homework Statement


See Image

Homework Equations



Source Transformations

The Attempt at a Solution



The answer is given, but I do not understand how they got it. When I multiply 9mA and 947.308Ω resistor, I get 8.526...what am I doing wrong? Also, could someone explain how they went on to get the final voltage in the simplified circuit. Don't you just add voltages when they are in series like this...?
 

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  • #2
8.526 V + 5.4 V = 13.926 V. So what's the problem?
 
  • #3
According to their calculation they got .947 V
 
  • #4
What does the Rf represent as well?
 

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  • #5
9 x 0.947 = 0.947 is obviously wrong, and looks like a typo.
It should be 9 x 0.947 = 8.523.
 
  • #6
I haven't built up a lot of confidence with circuit analysis, so I wanted to make sure that it was in fact an error on there part. Thanks guys.
 
  • #7
dwn said:
According to their calculation they got .947 V

For what? We need some context here.

dwn said:
What does the Rf represent as well?

Rf is the resistance in the op-amp feedback path.
 
  • #8
dwn said:
What does the Rf represent as well?

The feedback resistor. 150k + 0.740k in series.
 
  • #9
gneill said:
For what? We need some context here.

This is an online homework site and the guided solution provided a step-by-step solution, which is pictured in the first image I attached. AlphaZero already answered my question.

Thank you for the help.
 

1. What is an operational amplifier circuit?

An operational amplifier (op-amp) circuit is an electronic circuit that uses an operational amplifier as its main component. It is a high-gain, differential voltage amplifier with a very high input impedance and low output impedance. It is commonly used in electronic devices for signal amplification, filtering, and other mathematical operations.

2. How does an op-amp circuit work?

An op-amp circuit works by amplifying the voltage difference between its two input terminals. The op-amp has a high gain, which means that even small changes in the input voltage can result in a large change in the output voltage. It also has a feedback loop that helps to stabilize the output voltage and reduce distortion.

3. What are the different types of op-amp circuits?

There are several types of op-amp circuits, including inverting amplifiers, non-inverting amplifiers, summing amplifiers, difference amplifiers, integrators, and differentiators. Each type has a specific configuration and function, but they all use an op-amp as their main component.

4. What are the applications of op-amp circuits?

Op-amp circuits have a wide range of applications in electronics. They are commonly used in audio and video amplifiers, filters, oscillators, comparators, and voltage regulators. They are also used in instrumentation and control systems, medical equipment, and many other electronic devices.

5. What are the advantages of using op-amp circuits?

The main advantages of using op-amp circuits are their high gain, high input impedance, low output impedance, and versatile applications. They are also relatively inexpensive and easy to use, making them a popular choice among engineers and scientists. Additionally, op-amp circuits can be easily combined with other electronic components to create more complex circuits for specific purposes.

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