I am having trouble determining how to extract current value entering Analog Pin A0(reference to the picture) on Arduino Uno. Is that possible?
I am supposed to use said value in my code to create comparison with standard current in order to proceed coding the rest of the problem.
Is this a school assignment? Do you mean "voltage", not "current"?
Your circuit is putting negative voltage on A0 with no current limit, which will destroy the input and probably the whole chip.
The current into an input is negligible if you stay within the safe voltage range for the input.
1 Like
... if it is ever put on real hardware. So that learning experience might be missed. 
1 Like
This is a school assignment. I know that signal is actually voltage, but I need information about current.
That's why I was asking if its possible to get that value or not
How is the primary of TR1 connected? What kind of transformer is it?
It is a simple transformer. What I am trying to do here is simulating relay and recording the fault current as well as the response time for different values of R2 creating the short circuit everytime the push button is on. So, in my code I have to compare the current value with current pick up value as a condition to open the relay.
Also, thank you for taking the time to answer.
All transformers with two windings are simple. Come on. That's all you have for me? What are the specifications?
OK, that's a lot clearer in terms of what you want to achieve.
As I hinted in my first reply your rectifier output is the wrong way round, you are applying negative voltage on A0.
I have not done anything like you are asking but based on the circuit, not withstanding the incorrect rectifier connection, it, or something like it, should work. However, as @anon57585045 has said, more details are required. What exactly is the transformer, what are its specifications?
Looking back at your posts:
Yes it's possible you are having trouble determining the current you are trying to measure, or to answer the question I think you really meant, yes, I think it is possible to measure the current using the circuit you have, or something like it.
Apart from that you've not actually asked a question that anyone can provide a useful answer to. For a better answer things like your code, what you have tried, what difficulties you encountered are needed, along with specific questions.
@anon81327919 ,
I have just seen your flag to the moderators. We don't generally delete topics with replies because doing to wastes the time of the people trying to help. Deletion generally leads to a ban for this reason. You are getting help including hints on what you need to do to ask a question someone can answer.
I'm going to ignore the flag, now come back with better information.
Using an analog to digital converter you want to measure current with a device that measures voltage, correct?
Well, first refer to Ohm's Law.
If there was a low ohm resistor, 1 ohm, from the rectifier ground to the diodes then the ADC can read the small V drop across the resistor. The value read can be converted to a V. And using Ohm's Law of I=V/R one could calculate the current.
Maybe that transformer is supposed to be a current sense transformer.
I agree. There is another thread showing what looks like the same transformer, so the two posters are probably taking the same course, doing the same assignment. The other thread (which I regrettably can't find now), showed a more or less correct current transformer measurement circuit. This one looked more like a power supply circuit, before the complete schematic was posted. I certainly was fooled.
Yes, I expect that it is a current sense transformer. But I would like to hear the words come from the mouth of the original poster.
In that case, the current to voltage translation is already performed in the transformer load resistor. There are various circuits that provide matching and protection for the MCU input pin, probably the whole point of the exercise is to research and implement one of them.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.