Hi,

I am trying to design a circuit which does power measurments in an 120VAC line at home between the mains and the device in a digital form.

So far I realize that to measure power, I should use current sensing circuit like INA138 (http://www.ti.com/lit/gpn/ina138) and use its output to an ADC to get an output in a digital format.

Can the INA138 work with AC circuits in the first place? If not, are there any alternatives?

What is the best way to design a circuit that can be inserted between the mains and the device connected to the mains to measure the power used by the device in a digital format?

Please note that I am a 4th year Electrical Engineering student and will understand any complex terminology that you man use . I welcome all to comment on this =).

Thanks

 

120VAC will blow the lid right off an INA138. It's designed for low voltage.

Look at using Hall-effect sensors, or current transformers.

 

lol.

I realized that and that's why I would have used step down VT. It's not a very efficient method but I wanted to actually know if it would work with low AC voltages or not. So it will work with low AC right?

I found something else that would give me exactly what I wanna do.

I found ADE7753 (http://www.analog.com/static/imported-files/data_sheets/ADE7753.pdf). This is giving me all the readings that I want but this seems more complicated than just putting pieces together. It requires programming...

I will look into hall effect and CTs but in the meanwhile, do you think ADE7753 is nice and simple solution or can I do better from this list for single phase metering: http://www.analog.com/en/analog-to-...ent/products/index.html#Single_Phase_Metering

 

That is an awesome suggestion as well.

Thanks for the recommendations

 

This may sound stupid but I am doing this for the fist time. So I hope someone can answer this for me.

I am going to buy ADE 7566 (http://www.analog.com/en/analog-to-...rgy-measurement/ade7566/products/product.html). I want to program the chip but the problem is that I don't understand how I will do that.

I dont think the chip can be used with a breadboard. The pins look like they are for soldering only. I have no idea what I should solder this thing on or through what interface I can access it.

Can someone guide me?

Thanks.

 

It gets a bit intense. Try looking at the evaluation board material - http://www.analog.com/en/analog-to-...66_7169_7566_7569_eval_kit/resources/fca.html

The IC has to be mounted on a PCB, although you should be able to find a socket easily enough.

 

Thanks but the eval board is way too expensive!

Does anyone know if a BASIC stamp board (http://www.hvwtech.com/products_view.asp?ProductID=838) can help to program the chip?