Question with my circuit in multisim dealing with op-amp

In summary: The correct way to connect the circuit is to have the + end of the +10 V supply connected to one end of the potentiometer and the - end of the +10 V supply connected to the other end of the potentiometer.In summary, the person is having trouble constructing a circuit with +-10V supplies and a potentiometer. They explain that their original circuit had V2 upside down and was missing connections to the power supply pins for the amplifier symbol. After making changes, they are now getting a voltage of 88mV DC without the +-10 supply and 75mV DC with them connected, but changing R4 does not affect the Vc voltage. They later realize that the + end of the
  • #1
ee1215
29
0
I am drawing a circuit but not getting right result. I am to assemble the circuit below using +-10V supplies with all those specifications I have put in. I leave Node A open and adjust R4 to make Vc=0V. When I measure Vc originally it is about 10VDC(on the DVM). If I use a 100M resistor it only makes it about 3V. What is wrong with my circuit(the second link)?

Constructing:
http://i812.photobucket.com/albums/zz41/uofmx12/E21ckt.jpg [Broken]

My circuit:
http://i812.photobucket.com/albums/zz41/uofmx12/E21ckt_2-1.jpg [Broken]
 
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  • #2
V2 is upside down. You are supposed to have one end of the potentiometer be at +10 V, but you connected the + end of the +10 V supply supply to ground.

Also, you have not connected anything to what I presume are the power supply pins for the amplifier symbol.
 
  • #3
MisterX said:
V2 is upside down. You are supposed to have one end of the potentiometer be at +10 V, but you connected the + end of the +10 V supply supply to ground.

Also, you have not connected anything to what I presume are the power supply pins for the amplifier symbol.

Ok, so I changed the V2 supply. And I am getting about 88mV DC without the +-10 supply to the op amp and about 75mV DC with them connected. But for some reason when I change R4 resistor the the Vc voltage does not change from either 75mV or 88mV no matter what I change the resistor to. So I imagine something is still wrong.
 
  • #4
I figured it out
 
  • #5


It appears that your circuit is not functioning as expected. There could be several reasons for this, such as incorrect component values, a faulty connection, or a misunderstanding of the circuit's operation. It would be helpful to have more information, such as the specific op-amp model and the values of the resistors you are using.

One potential issue could be the open node at A. This could cause instability in the circuit and lead to unexpected results. I would suggest connecting this node to a reference voltage or ground to ensure proper operation.

Additionally, it is important to double check your connections and make sure all components are properly connected. Even a small mistake can greatly affect the performance of the circuit.

I would also recommend simulating the circuit in Multisim to troubleshoot any potential issues. This will allow you to make changes and see their impact on the circuit without having to physically rebuild it.

If you continue to have trouble, it may be helpful to consult a textbook or online resources for more information on op-amp circuits. You can also reach out to a colleague or mentor for assistance. Troubleshooting circuit issues can be challenging, but with patience and careful analysis, you should be able to identify and resolve the issue.
 

1. What is an op-amp?

An op-amp, or operational amplifier, is a type of electronic device that amplifies the voltage difference between its two input terminals. It is commonly used in electronic circuits for signal amplification, filtering, and mathematical operations.

2. How do I use an op-amp in multisim?

To use an op-amp in Multisim, you first need to select the op-amp component from the library and place it in your circuit. You will also need to provide a power supply and connect the input and output terminals of the op-amp to the rest of your circuit. You can then simulate and analyze the behavior of the op-amp in your circuit.

3. Can I change the properties of an op-amp in multisim?

Yes, you can change the properties of an op-amp in Multisim by double-clicking on the component and accessing its properties window. Here, you can change parameters such as the gain, input offset voltage, and bandwidth to customize the behavior of the op-amp in your circuit.

4. How do I troubleshoot issues with an op-amp in multisim?

If you are experiencing issues with the performance of an op-amp in your multisim circuit, there are a few steps you can take to troubleshoot the problem. First, check that the op-amp is connected correctly and that it has a suitable power supply. You can also try changing the properties of the op-amp or adding additional components, such as resistors or capacitors, to improve its performance.

5. What are some common applications of op-amps in electronic circuits?

Op-amps have a wide range of applications in electronic circuits, including audio and signal amplification, voltage regulation, filtering, and waveform generation. They are also commonly used in mathematical and control circuits, such as inverting and non-inverting amplifiers, differentiators, integrators, and comparators.

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