good morning YouTube so this is the little AC panel meter that I installed on my variable
isolated power supply so I picked up another one of these because I wanted to take a look inside
and see what makes it tick so let's do that okay so this is what you get in the Box you
get the meter here this is their little current transformer this is the AC power meter and then
here's the instructions had a couple of people ask you know are the instructions readable and
I guess you get one page of English and one page of Chinese instructions but it's reasonably good
covers the basic operation so if we look at the unit here again this is the PZ II M - a zero six
one and it appears that the piece fare is the manufacturer this one has zero to a hundred amps
a/c 82 to sixty volts it seems to work down to about sixty volts on the low end so it's a little
bit better than that range yes so here's the AC current transformer so this is what senses your
load current and it's about a 16 millimeter or 5/8 inch diameter inside the current transformer so
it would fit around a pretty large size cable and apparently it's rated at 1,000 to one so
for every 10 amps of current flowing through the middle of the transformer you get 10 milliamps of
current in the two wires and there are apparently some thousand to one split core transformers that
you could probably use with this in place of this because for instance if you wanted to install this
current transformer in your main breaker panel outside your house you would have to disconnect
the wire and then run it through the middle on like one of the split transformers where
you can open up the core and then clamp it over a wire there's also this open-source project called
the open power meter project and they seem to use a two thousand to one current transformer so you
have to be careful it seems like there's a lot of those open power monitor transformers available
but they put out half the current of this one you know mention that a little bit later here you get
the same wiring diagram your load goes through the current transformer those two wires come
in the side here the top two connections and then the bottom two are your AC voltage this comes off
those are the cover snaps off and then there's four little screws that hold the circuit board
in place and if we pop that out just to show you there's nothing on the backside you just have your
push button and the liquid crystal display here's your power terminals there's a one microfarad 275
volts this is your power supply essentially it's a capacitive dropper and underneath this capacitor
there's a bridge rectifier and a little 5 volt regulator for the rest of the digital circuits
and then you can see here this large resistor right there that is what senses the current in
here and it's about a 100 ohm resistor you've got these two wires hooked up across that resistor
and since this was a thousand to one so if you have a hundred amps flowing through this C T
you're going to have a hundred milliamps flowing through these two wires shorted them or if you
put those across that resistor a hundred ohms with a hundred milliamps is 10 volts so you're
going to get 10 volts full-scale across there resistor if you wanted to change this to work
with a different transformer say you had a 2,000 to 1 transformer you could change that resistor
output a 200 ohm resistor and get the same 10 volt reading with a 50 milliamp input so let's
take a look here at the chips there's basically three large I C's on here this is a renergie or
Sun Shine science are an eight to zero 8g which is a single-phase metering IC so this takes the
voltage waveform and the current waveform and does the power factor calculations and produces the
instantaneous voltage current and power and then this is a three point five seven nine megahertz
clock which forms a real-time clock because this thing needs to know about seconds and minutes and
hours because it needs to compute kilowatt hours or watt hours and I'll put links to the all of
the chips in the video description and then this is the brains of the unit this is an ST micro 32
F 0 3 0 so it's an 8 megahertz microcontroller that's the crystal for it there's your st-link
for p5 pins I guess this is the other chip this is a whole tech ht1 six to one it's a ram mapping
32 by 4 LCD controller so that's pretty much the inside of the device just the three ICS and like
I said there's your power supply AC side over here so anyway that's my inside look on one of
these are pretty good build quality and there's there's a bunch of interesting variations on this
and also I've had a few viewers pass on some interesting part numbers and information like
on the finding ratio of this current transformer you know I'll try to get a hold of a couple of
those other variations on this and we'll take a look at those and as always thanks for watching