I described what is essentially a DIY clamp ammeter.

Ahaa, interesting idea. Did you find the circuit for it? or still searching it?

it might be nice to use it for an atmosphere monitoring display. Use one of the kit boards from sparkfun or adafruit that monitor air quality (there are a number of metrics and there are a number of boards to detect each metric) and you could have a little readout on say pollen count or carbon monoxide. Hell or barometric pressure. There are a lot of ideas that could work.

Not bad .. but for all these dont I need special sensors? Can you put a circuit for one?

 

I described what is essentially a DIY clamp ammeter.

And for @wayneh idea, here is a cct I find for AC meter:
https://www.homemade-circuits.com/ac-ammeter-circuit-for-measuring-current-across-220-v-appliances/

and also this clamp meter, but the page does not exist anymore, only the image stored in google servers.
Interestingly enough is that I could not find any tutorial on AC /clamp/or/normal/ amp meter. They are strategically removed from the internet. Or I have a very big bad luck on finding them. Hmmm. I can only find DIY DC amp meters circuits and the internet is inundated with them.
I also find this https://en.wikipedia.org/wiki/Hall_effect_sensor using a Hall effect sensor to measure DC current (not AC). Scroll down to Ammeters section.

 

View attachment 336270
and also this clamp meter, but the page does not exist anymore, only the image stored in google servers.
View attachment 336271

That's just a current transformer driving a meter via a rectifier.

 

I built a circuit that read the 0.5 kWh pulse flashes from my power meter and calculated the instantaneous kW from the time between flashes, then displayed the resulting power rate on an analog meter. A PIC 12F615 timing the pulses with a PWM output to drive the meter. Some fun assembler and meter rescaling on a 270 degree movement:

 

The image at the top of post #22 is exactly what my comment was advising against.

(applied to the entire house)

 

The image at the top of post #22 is exactly what my comment was advising against.

(applied to the entire house)

And I agree - don't do that. Use ONLY the non-invasive sensor, like the 2nd image.

 

Just a couple of related links that might trigger some thoughts:
https://www.amazon.com/Current-Ampe...ansformer/dp/B07JB9B2QL/ref=asc_df_B07JB9B2QL
https://hackaday.com/2019/07/27/building-a-safe-esp32-home-energy-monitor/

 

Makers Make a clock out of three meters.


hacksters Here is another one youtube video

 

The image at the top of post #22 is exactly what my comment was advising against.

(applied to the entire house)

That's how it is done in a modern electricity meter:
https://www.analog.com/media/en/technical-documentation/data-sheets/ADE7903.pdf

 

Yes...designed, built and installed by professionals.

 

That's how it is done in a modern electricity meter:
https://www.analog.com/media/en/technical-documentation/data-sheets/ADE7903.pdf

- Heh, thats an interesting internal circuit actually. But all this is pure digital conversion and reading through all those 3 ADC's that are sending the data directly to a MCU. And is true, it is more professional this way. Very interesting IC indeed, mister IAN0.
- What Im doing here is only a very quick and dirty thing, the focus is over the meter itself to find an interesting and hopefully practical project to mount in. I dont care what it is used for or how perfect reading is doing_haha. I only care to not put this meter back in its box because it will remain there for another 20years.

 

You guys, have all those wonderful vintage electronic magazines from the 40's - 70's - 80's - 90's - 2000's. Cant you open some and look into and pick for a quick idea from there? I have some romanian old magazines from 70's-80's that mostly got influence by russians, germans and polish circuits at the time, translated into romanian lang basically. But not american circuits or uk ! Im not saying they are bad, they are actually very good, simple and easy to make for everyone. But they are from this part/side of the world where I live. I have a few, maybe 20? on paper stored on my shelves. But I remember I also have the pdf's of almost the entire collection of them.

 

- Heh, thats an interesting internal circuit actually. But all this is pure digital conversion and reading through all those 3 ADC's that are sending the data directly to a MCU. And is true, it is more professional this way. Very interesting IC indeed, mister IAN0.
- What Im doing here is only a very quick and dirty thing, the focus is over the meter itself to find an interesting and hopefully practical project to mount in. I dont care what it is used for or how perfect reading is doing_haha. I only care to not put this meter back in its box because it will remain there for another 20years.

I was surprised at the circuit. I would have expected a current transformer and a small signal transformer such as ZMPT101 for the voltage.
But if you want to measure your mains current then a 100A:30mA current transformer and a Schottky rectifier would do just nicely.

 

But if you want to measure your mains current then a 100A:30mA current transformer and a Schottky rectifier would do just nicely.

What about a single resistor that will limit to around 30mA and a rectifier diode probably 1N4148 will be good enough because the current is very small. Even a TS4148 SMD diode.
But after measuring the mains current...then what? it will stay at that 30mA, which is the max of the needle travel. What I can actually measure with it?

 

Hello,

For old magazines and books, have a look at this thread:
https://forum.allaboutcircuits.com/threads/library-of-old-books-magazines-and-textbooks.142550/

Bertus

 

Hello,
For old magazines and books, have a look at this thread:
https://forum.allaboutcircuits.com/threads/library-of-old-books-magazines-and-textbooks.142550/
Bertus

thanks ill look into it. Im actually a collector of these magazines. Not a great/good one, but one, haha.
Here is what I have :


I was wondering if this website AAC, since it helped me along the way all these years, maybe I can contribute to it with my gathered collection I have here. The only downside is a bit of space to accommodate all these. I think is a good idea to have all countries electronic magazines pdf's in one place, public and free to look into. Or Im too old fashion?

 

You guys, have all those wonderful vintage electronic magazines

Well, it was a very bad idea...
- I started to look into MY romanian collection for an example but .... aaaaaaaaaaah, there are so many random subjects I must pay attention what they do, to understand its not what I want, and they are soooooooo undated, they are mainly for the technology at those times, I forgot completely about it, hacks for trabant, dacia, skoda, cars, electronic hacks or adapters or addons for pickup vinyl, BW TV's, lamp radios, dark room photography laboratory hacks, house hacks - furniture, repairs and hacks, even an electronic starting oil lamp circuit - hahaha, like how to make a remote control with a 3V light bulb, haha, waaaay too undated. They are cute because they mean a bit of nostalgia from my part because I grew up with a few of those magazines in my hands as a child, 2 or 3 literally, and I know very well how POOR times those were and how much lack of resources it represented those times. Later in life I realized its an entire series of these magasines. Yah, its too much pain and too much effort to search into all that data, quite random and very undated. And if there are some good circuits there, its very hard to find them.
- I spoke privatly with mister @bertus and among his links I found a quite good miniseries : https://archive.org/search?query=neets&and[]=subject:"Electronics"&and[]=mediatype:"texts" that I put it aside:

 

What about a single resistor that will limit to around 30mA and a rectifier diode probably 1N4148 will be good enough because the current is very small. Even a TS4148 SMD diode. View attachment 336327
But after measuring the mains current...then what? it will stay at that 30mA, which is the max of the needle travel. What I can actually measure with it?

You can measure the mains current.

 

You can measure the mains current.

yes I get it, but my mains current does not fluctuate like @wayneh said it is in his side.
What else I can use it for?

 

Hello,

You can find some old magazines and more at bitsavers:
https://bitsavers.org/

Bertus