Analyse du circuit d'amplificateur opérationnel - Calcul de la sortie
Table of Contents
- Introduction
- Understanding the Circuit
- Analyzing the Feedback
- Applying the Virtual Short Concept
- Finding the Loop Gain
- Deactivating Independent Sources
- Redrawing the Circuit
- Identifying the Lack of Feedback
- Circuit as a Comparator
- Potential of the Positive and Negative Terminal
- Output Calculation
📝 Analyzing the Circuit for Output Calculation
In this article, we will analyze a small but tricky circuit to determine the output. The circuit at HAND acts as a comparator and we need to find the potential of the positive (V+) and negative (V-) terminals to calculate the output. Let's dive in and break down the circuit step by step.
1️⃣ Introduction
Here, we have a circuit with an ideal Operational Amplifier (OPAMP) and our goal is to find the output potential (OPM). The OPM is assumed to have an ideal gain of infinity. To analyze this type of circuit, we first need to determine if there is any negative feedback Present.
2️⃣ Understanding the Circuit
To understand the circuit, we need to check if negative feedback exists. If there is negative feedback, we can apply the virtual short concept. According to the virtual short concept, the inverting and non-inverting terminal potentials of the OPAMP are equal. However, we cannot directly assume negative feedback based on signs. We need to find the loop gain.
3️⃣ Analyzing the Feedback
To check the feedback, we need to find the loop gain. We do this by cutting a point on the loop, traversing the loop, and returning to the starting point. We then check if there is a 180° phase shift. However, in this circuit, we won't calculate the loop gain.
4️⃣ Applying the Virtual Short Concept
Since there is no loop gain calculation required, we can directly determine if there is feedback. Let's redraw the circuit and analyze it further.
5️⃣ Finding the Loop Gain
In the circuit, we have resistors with values of 1K each. The current source is independent. To find the loop gain or check the feedback, we observe that no current passes through the current source. Therefore, there is no feedback present.
6️⃣ Deactivating Independent Sources
Since there is no feedback, we can assume a zero potential at the inverting terminal. After redrawing the circuit, we can see that the potential at the inverting terminal is zero, and the non-inverting terminal has a potential of zero as well.
7️⃣ Redrawing the Circuit
Redrawing the circuit with the given potentials, we can see that the circuit acts as a comparator.
8️⃣ Identifying the Lack of Feedback
As there is no feedback present in the circuit, we can determine the potential at the positive and negative terminals. Upon analyzing the circuit, the potential at the negative terminal is -1V, and the potential at the positive terminal is 0V.
9️⃣ Circuit as a Comparator
The comparator works based on the potential difference between the positive and negative terminals. If the potential at the positive terminal is greater than the negative terminal, the output will be a positive voltage (V+). Conversely, if the potential at the negative terminal is greater, the output will be a negative voltage (V-).
🔌 Potential of the Positive and Negative Terminal
In the given circuit, the potential at the negative terminal is -1V, and the potential at the positive terminal is 0V.
🔌 Output Calculation
Since the potential at the positive terminal (0V) is greater than that at the negative terminal (-1V), the output will be a positive voltage. Based on the given information, the output voltage of the circuit is +5V.
🎉 Highlights
- The circuit is a small but tricky one.
- The circuit acts as a comparator.
- The potential at the positive terminal is greater than at the negative terminal, resulting in a positive output.
❓ Frequently Asked Questions
Q: What is the purpose of finding the loop gain in this circuit?
A: The loop gain helps determine if there is negative feedback in the circuit. However, in this particular case, there is no feedback present.
Q: How is the output voltage calculated in this circuit?
A: The output voltage is determined by comparing the potential at the positive and negative terminals of the circuit. If the potential at the positive terminal is greater, the output will be positive; if the potential at the negative terminal is greater, the output will be negative.
Q: Why is the circuit considered a comparator?
A: The circuit acts as a comparator because it compares the potential at the positive and negative terminals and outputs a positive or negative voltage accordingly.
Q: What is the purpose of the virtual short concept?
A: The virtual short concept helps simplify circuit analysis by assuming that the inverting and non-inverting terminal potentials of the OPAMP are equal.
Q: Can the output voltage be negative in this circuit?
A: No, since the potential at the positive terminal is greater than at the negative terminal, the output will always be positive in this circuit.
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