dc current transformer

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franticET

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Hi to all and happy new year!!!

I'm studying the circuit in figure below


and i don't understand how it's work, from a theoretical point of view, when the uC pin is 1 or 0.

I've made some simulations and i've noticed that the square wave on the output is amplified when the pin is at high logic level, so +15V on R1. That's true?

Could you give me some help in understanding? Thanks
 
first of all, what is a dc current transformer? Transformers are purely AC only.
Where does that circuit come from? It seems rather weird to me, i´d expect to see a diode here and there if it is supposed to be a dc supply.
 
What is the triangle at the top with +15V but no ground?
Are the two outputs from the uC in-phase? If they are in-phase then they are the same and only one is needed.
 
kubeek said:
first of all, what is a dc current transformer? Transformers are purely AC only.
Click to expand...
There are DC current transformers.

A DC current will produce a magnetic field that doesn't change. Voltage will not be induced in a winding by a magnetic field that doesn't change, but if another method of measuring the field is used, then the transformer can measure the input current.

The field is often measured with a Hall sensor or a fluxgate sensor. For better accuracies, the magnetic field is controlled to zero by a sense winding with lots of turns.

https://www.lem.com/ offer loads of current transformers, and most if not all will work at DC.
 

But that's not a transformer? - it's a hall effect device (or something else) measuring the magnetic field of a coil or conductor.

The website you linked to mentioned 'transducers', I couldn't see any mention of DC transformers.
 
Nigel Goodwin said:
But that's not a transformer? - it's a hall effect device (or something else) measuring the magnetic field of a coil or conductor.

The website you linked to mentioned 'transducers', I couldn't see any mention of DC transformers.
Click to expand...

You are right, they are transducers.

The original question was about DC current transformers. The most common use of current transformers is for current measurement, where a large current can be reduced (and the voltage isolated) so that an indicator can be used without the voltage drop or high voltage issues. Current transducers like that will behave in similar ways for DC, but being transducers they do not transfer any power, so they need separately powering on the secondary side.
 
audioguru said:
What is the triangle at the top with +15V but no ground?
Are the two outputs from the uC in-phase? If they are in-phase then they are the same and only one is needed.
Click to expand...
It is a buffer that is 5V tolerant but its output is 15V logic level signal
 
Diver300 said:
The original question was about DC current transformers.
Click to expand...

Which don't exist - 'transducers' are used for DC, 'transformers' only work for AC.

The transducers require secondary power in order to feed the electronics, such as the hall sensor (which measures the magnetic field) and associated amplifier.
 
Perhaps the word 'transformer' in the Title, is in the context of transforming DC to AC, ie: an Inverter.?
 
The circuit is full of ambiguities and unless you have seen something similar before, all you can do is sit scratching your bits until the OP comes up with a bit more information/clarification.

JimB
 
ericgibbs said:
Perhaps the word 'transformer' in the Title, is in the context of transforming DC to AC, ie: an Inverter.?
Click to expand...

It looks like a SMPSU, badly drawn, with plenty of mistakes

The major one is no rectifier diode on the feedback winding.
 
Hi,

I think it would be a good idea for the OP to tell us what this circuit is supposed to be doing in the first place, which may include a little info about what the uC is supposed to be doing.
I say this because at first glance it looks like a 'generator' circuit of some kind where the uC is trying to generate some kind of signal that appears at the output of the 'current transformer'.
A current transformer used in reverse is just a step down transformer that can be used to generate a high current low voltage signal from a low current higher voltage signal.
Just a guess but everything seems to be flowing from left to right in the diagram.
 
I tried to sim it in LT spice, but I lack the spice know how, I will keep trying as it looks like a great circuit to sim
 
Looks like a magnetic amplifier to me. DC current in the top primary controls the degree of saturation of the core, hence the amplification of the signal applied to the lower primary.
 
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