I have a circuit that I have implemented from a research paper in LTSpice. I want to now implement it in hardware like breadboard and then on PCB zero maybe. I had some doubts since I am a beginner, like how do I power the op-amp, generate the volatges in mV, and the current in mA. If anyone can please reply then I can get into in details. Thank you.

 

How stable and accurate do the mV and mA sources need to be?
What resistor value tolerance is allowable?
Have you considered op-amp limitations/characteristics, such as input bias currents, slew rate?
Do you have a budget for this project (which might affect your choice of op-amps etc)?

 

how do I power the op-amp

You use batteries or a power supply.

generate the volatges in mV, and the current in mA.

Voltage and current for what purpose?

 

Where did this circuit come from?

I can pretty much guarantee that your circuit will never work properly, if at all, if you implement it using discrete components. There are many long-tailed pairs in that circuit, and such topologies rely on very close matching between the transistors involved. You will never get that without a LOT of characterization effort and cherry-picking your transistors and, especially with a general-purpose transistor like the 2n2222, as soon as the temperature changes from self-heating, the circuit will start drifting and probably saturate very quickly.

It looks like whoever designed this circuit never actually built it, but instead relied on simulation results. By default, simulation devices are perfectly matched and you have to put in some effort to model the significant mismatch effects by setting up a decent Monte Carlo simulation. This is an easy trap for someone to fall into until they gain some experience. In this case, I'm guessing they took a schematic of an ASIC implementation and just threw the first transistor to come up in a dialog at it. They are also using very highly idealized models for the opamps.

 

How stable and accurate do the mV and mA sources need to be?
What resistor value tolerance is allowable?
Have you considered op-amp limitations/characteristics, such as input bias currents, slew rate?
Do you have a budget for this project (which might affect your choice of op-amps etc)?

The volts and ampere have to be precise. The budget is flexible I don't have many constraints. I did read about slew rate which plays a role since my voltage signals are very high frequency.

 

Where did this circuit come from?

I can pretty much guarantee that your circuit will never work properly, if at all, if you implement it using discrete components. There are many long-tailed pairs in that circuit, and such topologies rely on very close matching between the transistors involved. You will never get that without a LOT of characterization effort and cherry-picking your transistors and, especially with a general-purpose transistor like the 2n2222, as soon as the temperature changes from self-heating, the circuit will start drifting and probably saturate very quickly.

It looks like whoever designed this circuit never actually built it, but instead relied on simulation results. By default, simulation devices are perfectly matched and you have to put in some effort to model the significant mismatch effects by setting up a decent Monte Carlo simulation. This is an easy trap for someone to fall into until they gain some experience. In this case, I'm guessing they took a schematic of an ASIC implementation and just threw the first transistor to come up in a dialog at it. They are also using very highly idealized models for the opamps.

This circuit is actually from a research paper https://link.springer.com/article/10.1007/s11071-016-2647-y
I don't mind changing the components to some other ones which are better suited. I need to figure out how to ensure that the voltage and current are precise when in order of milivolts and milliamps and also how to multiply these signals.

I am attaching my circuit here, https://www.dropbox.com/scl/fi/ziou...ey=uskvrusmrosn1118ble1zwr3u&st=k92g9283&dl=0

 

You use batteries or a power supply.
View attachment 367792
Voltage and current for what purpose?

I wanted to look at alternatives to power this circuit in hardware not in simulation The voltage and current which are provided as input are in the order of 10*e-3, some of them so I need to figure out how to power the circuit.

 

The volts and ampere have to be precise. The budget is flexible I don't have many constraints. I did read about slew rate which plays a role since my voltage signals are very high frequency.

And you are all-but guaranteed not to get, and keep, the volts and amperes precise enough if you implement it using discrete components, no matter what your budget it. The original circuit was likely implemented as an ASIC.

 

This circuit is actually from a research paper https://link.springer.com/article/10.1007/s11071-016-2647-y
I don't mind changing the components to some other ones which are better suited. I need to figure out how to ensure that the voltage and current are precise when in order of milivolts and milliamps and also how to multiply these signals.

Since I'm not going to pay for a subscription to Springer to access the paper, it does me little good.

Read the paper and see if you can clearly determine whether they implemented their circuit using discrete components or whether they implemented as an ASIC. There are probably telltale signs even if they don't state it outright.

 

Posting a circuit in the simulator .asc format was not a nice trick! It does not open for me because I do not use that simulator software. When posting a file here, please ALWAYSinclude the file extension.
Now we are told you want to build it.
BUT " I have a circuit that I have implemented from a research paper " tells me it is already built.
(the rest of my coment is deleted.)

 

Posting a circuit in the simulator .asc format was not a nice trick! It does not open for me because I do not use that simulator software. When posting a file here, please ALWAYSinclude the file extension.
Now we are told you want to build it.
BUT " I have a circuit that I have implemented from a research paper " tells me it is already built.
(the rest of my coment is deleted.)

The file extension was included.



When I downloaded it, it saved it with the .asc extension.

"I have a circuit that I have implemented from a research paper in LTSpice. I want to now implement it in hardware like breadboard and then on PCB zero maybe."

Tells me that he implemented it in a simulator and now wants to implement it in hardware (though I don't know what "PCB zero" means -- maybe a perf board or something similar?).

 

The file extension was included.

View attachment 368198

When I downloaded it, it saved it with the .asc extension.

"I have a circuit that I have implemented from a research paper in LTSpice. I want to now implement it in hardware like breadboard and then on PCB zero maybe."

Tells me that he implemented it in a simulator and now wants to implement it in hardware (though I don't know what "PCB zero" means -- maybe a perf board or something similar?).

yes basically perf board where the passives are soldered on manually

 

I very much doubt that a perf board construction, with all its stray impedances, would give you the accuracy you want.

 

I very much doubt that a perf board construction, with all its stray impedances, would give you the accuracy you want.

I'm far from convinced they actually built the thing -- everything in the paper look like nice, clean simulation results. They never mention offset and matching issues, which are going to be a big problem with using discrete differential transistor pairs, and the fact that they are using 2n2222 and uA741 components makes me think that they are just throwing the classic textbook parts at a simulator.

 

For DC circuits, and those using low frequencies,, GOOD "perf board assembly" would be quite adequate. That means a clean piece of board to start with, and enough constructor skill to produce a physically solid assembly. That is not a trivial requirement! And for accurate measurements that agree with the simulations probably 1% resistors, or at least selected ones that are close to the claimed values.