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PRITAM the cat of Ne
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- Homework Statement
- What is the output voltage Vo of the OPAMP circuit given below?
- Relevant Equations
- V=IR
It's kind of a trick question. Since the + input is grounded, it doesn't matter what voltages are on the other sides of the bottom 3 resistors. And 2 x 0 = 0V still.PRITAM the cat of Ne said:Homework Statement:: What is the output voltage Vo of the OPAMP circuit given below?
Relevant Equations:: V=IR
it is expected that Vo is 0V!
Welcome to PF.boo said:The noninverting terminal is NOT at zero volts. Do a KVL there and you will find that the voltage there (and thus at the inverting terminal as well) is equal to 2*V. Then do a KVL at the inverting terminal and you will find that the gain is, indeed, 6.
No, there is nothing strange going on here, except for the circuit schematic error (or connection error if somebody tried to build this). No power supplies are stressed, no assumptions of ideal opamps, etc. The problem is just that the error keeps those 3 voltage sources from being able to change the voltage of the + opamp input. The current in each of those 3 branches is just ##\frac{V_i}{R}##, and those 3 currents are sinked to ground leaving 0V at the + input.boo said:OK, so here's why I still think that the non-inverting terminal has voltage = 2*V and not zero. I assume that this problem assumes IDEAL voltage sources. Now by placing that ground at the end of those 3 parallel voltages sources (hanging off the non-inverting terminal) you have effectively shorted them out. You have made the voltage on the "positive" end of that circuit equal to the "negative" end with both at ground potential.
Now the problem here is that you cannot short out an ideal voltage source. By definition an ideal voltage source will deliver ANY current to maintain the stipulated voltage. Thus KCL at the non-inverting terminal will still show 2*V volts (and thus the output voltage 6*V).
The non-inverting terminal is at zero volts. The inverting terminal is therefore at zero volts, unless you are given an offset voltage or you assume the opamp will run against the rails and you are given that voltage or some additional information you have not posted. The KVL equations do not give a gain of 6. You have:boo said:The noninverting terminal is NOT at zero volts. Do a KVL there and you will find that the voltage there (and thus at the inverting terminal as well) is equal to 2*V. Then do a KVL at the inverting terminal and you will find that the gain is, indeed, 6.
To troubleshoot an op-amp circuit output, you should first check the power supply to make sure it is providing the correct voltage. Next, check the input and output connections to make sure they are properly connected. You can also use a multimeter to measure the voltage at various points in the circuit to identify any potential issues.
There are several reasons why an op-amp circuit output may not be working. It could be due to incorrect component values, incorrect wiring, or a faulty op-amp. It is important to check all components and connections to ensure they are correct and functioning properly.
The gain of an op-amp circuit can be calculated by dividing the output voltage by the input voltage. This is known as the voltage gain. The formula for voltage gain is A = Vout/Vin. You can also calculate the gain in decibels (dB) using the formula A(dB) = 20log(Vout/Vin).
A feedback resistor is used in an op-amp circuit to provide stability and control the gain of the circuit. It creates a feedback loop that helps regulate the output voltage and minimize any fluctuations or noise. The value of the feedback resistor can also determine the overall gain of the circuit.
When selecting an op-amp for your circuit, there are several factors to consider such as the required input and output voltage range, the desired gain, and the frequency response. It is important to choose an op-amp with a high enough slew rate and bandwidth to meet the needs of your circuit. Additionally, you should also consider the power supply requirements and the cost of the op-amp.