before I start off this video here is a
summary of current sensors and there are
different parameters for what I think is
important to be when considering what
type of contents you're going to use if
you came for this video for just a quick
overview here it is please pause the
video take a screenshot and you can find
out the different types of current
sensors they are in a brief and a brief
indication of how effective they are and
you can choose from there stick around
for the rest of the video to find out a
bit more into detail about three of them
I have spoken about I hope you enjoy the
rest of the video so here I am on a
website himaroni and it's a and here
I've got a Ina i n a169 analog DC
current Center breakout 60 volts 5A Max
this is something I've used a lot in my
own projects before that I've had to do
as a project for I had to test multiple
samples and I multiplexed them all into
the ADC of an Arduino to test the proof
of concept thing to see if we can
measure the resistance of these samples
with a voltage is applied to them and
whatnot and we use this to get the
accurating ohms saw do I know if it was
the right way there's probably so many
other better ways to do it but that's
the point besides the point of this
video taking a look at this this is
there are a few ways there are a few
ways to measure current and it can
either be indirect or directly in this
case this is a direct method because it
is literally passing through a shunt
resistor where you need to bulge the
wires and get thing in through it the
need to polish the wires and pass a
current through the shunt resistor here
if you do not know these shunt resistors
are current sense resistors otherwise
and they drop a voltage across it and it
usually picks it up through here and it
probably takes a reading out of it and
outputs it into your in the output as a
millivolt and then your ADC you can read
it so on so forth and you're thinking
okay so what I I could usually Implement
yes so could I implement this could I do
the exact same thing in in my project
yes you can you definitely can there's
no harm in that you definitely can do
that and we'll take a look at the data
sheet let's find out let's find out what
do you actually need here we are in the
data sheet i n a169 it's a high side
unipolar current shunt monitor why
voltage range tiny so salt 23 package
and use a variety of applications like I
said before I've used this a lot in the
past and it's brilliant absolutely
brilliant just to get something quick
and going easy easy to do so what are we
looking for when we come to this as I
said before these can be either indirect
or direct so first what type of method
do you want because then that's indirectly
indirectly
um might not be so invasive for your
purpose or something that's direct you
don't want you putting this in the
circuit or something take a look we're
going to be looking at a an indirect map
a few methods really throughout this
video so this is one method and you look
through it you're looking for the
operation you want to understand how
this device works so you can implement
it fairly straightforward the shunt goes
across here there's a load power supply
slide and externally to it through here
okay this will be the same one passes
through a shunt resistor and comes out
to your load gives you some values of
the voltage gain here of what you want
to expect and with the resistors it's
very easy very easy to set up and get
you going I would highly recommend you
read this part of the data sheet it
really really helps so I do highly
recommend it over here usually in these
days they always give some sort of
application and it's easy to get you
going see it's really that simple
nothing too complex about it again this
is one of the more popular ones so if
you just follows if you just followed
what it says you can easily implement
this and if you're really that lost
refer to these modules they they come
ready plug-in easy to use use that for
your proof of concept if that's what
you're doing or just copy the layout
design from this easy and these models
are not expensive the chip will be even
less from so expensive don't worry about
it so let's look at a different method
an indirect method for your project
let's take a look at this zmc t103c
current sensor module AC another popular
another quite popular current sense
module and this one I haven't been fond
of with the project that I am going into
but for your case if you're looking for
that Innovative so even the project I
plan to do is going for this week's off
purpose you can already see that we have
a donut shaped hole here and you can
really think oh I guess I'll Chuck the
wire through it yes that is exactly how
it does let's see how it works then
shall we so how is this actually working
I've got a brief dial diagram laid out
here and as you see the image is quite
self-explanatory so this would work by
first applying your wire through as for
reference through the the donut shape
conductor and by passing through this
wire it measures the change in the
magnetic field because it's an AC signal
and this would be act as your primary
coil now this is a current Transformer
so if you know how the basic operation
of transform work the same principles
apply your primary and secondary coil
and so this coil over here the secondary
one is essentially stepping it down from
your primary is it not smart and because
I said before the change of a magnetic
field we get a step down output because
of our secondary coil so we look at the
data sheet of this device and this is
actually just the the component itself
the current Transformer you may be
wondering well what is that electronic
component that was there I saw way more
components than that well if you look
over here you see the directions for use
we actually see we have a off amp over
here and it's because it is as you know
no problem is the amplifier signal and
the current Transformer you're getting a
very minuscule signal it may not even be
readable by our ADC that of our choice
this can be just plugged in straight
into a microcontroller like so in this
diagram I'll put on screen and this
op-amp over here is just applying that
to read both like Max 3v3 signal
essentially so that's all that's all it
is it is literally just this sensor and
an op amp it's how a lot of similar
things work with dating small signals
it's it's quite surprising actually when
you come around to it so let's take
example for it and completely off topic
but it's like for example EMG muscle I
don't know Electro muscle or something I
don't know I'm not too sure um so what
it is it sticks on your muscle and then
bike flexing or Contracting your muscle
it generates a small output voltage from
that signal and the signal is just
Amplified and that's how you get a
reading on to what is actually happening
so you see a lot of these similarity
it'll be like with the more technical
difficult stuff you've seen a lot more
but this is just the basic concept of
how it is so another popular method is
this hall effect sensor here which we're
looking at the data sheet it tells us
tells us exactly what it is gives us a
bit about these features description and
nicely a tip typical application circuit
which is always very useful and
typically comes with these data sheets
as per usual it is similar to any other
IC do not treat this as well as like
something special always comes in as
like always time and time again they
want to make it as easy as possible for
them for you to integrate their stuff so
you can come back and buy more let's
take a little bit of a look at it and
see what's there see what we can derive
from this and from this we are going to
take a look at how do we determine
something is fit for our needs so I
think the first thing is first is before
it's range and everything Supply voltage
is it worth can we use this in our
system so even just look at the typical
applications is 3.3 or 5 volts and
bypass where there's 0.1 microfarad
capacitor and this is pretty standard
amongst the embedded system designs or
whatnot you're usually working with them
these low voltage ranges oh that seems
to be good of course we can find this in
our specification also here we are in
the common operating characteristics
three to five point five typical five
volts but if you can use 3.3 really
Supply current it is quite a bit so
maybe keeping your mind but I don't
suppose you are constantly measuring
this maybe every so often if you're
doing some measurement unless you're
having some feedback loop I don't know
what you're doing but if you have a
battery powered device maybe it is to
worth keeping mind especially very
important like portable ones and such so
we've got that out the way what else are
we looking for let's look at its offset
to see if it's something that's really
critical to us so this output voltage
here we see it may drift over time as
much as 25 millivolts but I don't think
that is that much in our case so we're
going to keep looking we see different
types of things so I'm guessing this is
the model so we have different things
here 105 150. I'm guessing it's the
different models that they provide and
whatever model you choose how this but
maybe take this 151 over here electrical
offset voltage this is the drift is
referred to Ideal VL equals 2.5 volts
and we can see at certain parameters and
test conditions that we can get if
you're working between the 25 degree
ambient temperature 25 to 125 maybe we
get a 14 millivolt offset and my minus 4
to 25 we get a 24 millivolt offset so
that is keep in mind how accurate you
want your system to be if it's just a
basic refrigerant measurements I don't
think it really matters that much of
course this is all depend on your
project so things to keep in mind so for
that even we're wondering well the range
what what can we even range like what
what can we measure so looking at this
I'm assuming the primary sampled current
is what we can actually measure we see
zero to 100 minus 100 to 100 so 0 to 50
is quite a bit it seems like do 80 and
DC so this is quite quite big actually
we could probably use it with Mains and
now we are looking for its voltage which
I assume would be just as equal as as
much and fully capable so it's not
really clear with these if you specially
don't really know what you're looking
for but here we find in the isolation
characteristics that we can see the
working voltage for basic isolation and
Direction test strike so these are the
subsano tests that they go through and
we see we get a 700 vrms 990 VDC or V
Peak VPK even on a quick Google search
you may be able to find something if you
are not too certain and it's so it's not
that confusing so quick Google search
you see someone else has done it says
magnetic interface that automatically is
isolated rated for voltages up to 700 V RMS
RMS
so as you can see it's quite a bit that
it can really take and of course there
are other parameters that you may be
interested but I think these will be the
main one the supply voltage what its
current measurement and voltage
measurement to drift or it's offset if
you will see what else you might need
and anything else I think quick Google
or what have not but this is just to get
you started what measurement techniques
are available to you when you are
exploring this topic now before we end
off the video I'd like to show you a bit
of a summary sheet so I have a bit of a
summary table here for your reference
really if you ever wanted to see and in
this table I'll briefly go over a few so
here are five methods of measuring
current there are shunt hall effect
current transfer Rogowski forgive me I'm
probably pronouncing that wrong zero
Flex so if the connection type the
current accuracy range drift in
isolation now the isolation one is when
we saw the the vrms value and it's
isolated because inside that IC there
was actually a hall effect on this was
not actually passing through it's
instead sensing it so that is why and
you can tell the isolation you can see
for the current Transformers passing
through something it's not directly
connected and but for the Sean one you
saw we had to pass it through something
and that's why it's there's no isolation
in between so there's something else you
need to keep in mind but between
choosing something for your projects I
would keep these few parameters in mind
to see what you are measuring and I hope
this table comes in helpful so please
pause the video take them take some
notes if you really have to take a
screenshot and hopefully this helps you
in this part of what you think and what
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