how to measure 230 V AC by pic without transformer

[BoopathiRaja]

Hi.. Friends..

I need to measure 230VAC Variation by PIC microcontroller without using transformer.

I already tried by using transformer, its big one for my application and not suitable.

Plz tell me any other method to monitor AC voltage by Micro Controller........

τ Regards τ

Raja

 

[IanP]

Goto (p.5):
https://www.electro-tech-online.com/micro-controllers/85112-how-detect-exceed-ac-voltage-5.html
and have a look at several examples of circuits (no transformer means no isolation) that can be used as an interface between the mains and PIC's ADC ..

IanP
:|

 

[pranam77]

Frankly specking using a transformor is the safest means of mesuring AC with a PIC micro. You may use voltage divider network built with resistors to drop the voltage to the required levels, but i dont recomend connecting it to the Micro. On the contrary, you may explain what problems are you facing with the transformor based design so that you may get better soluttions form fellow members.

 

[BoopathiRaja]

Hi.. pranam77

i am using 230 VAC measurement in 3 places of my application.. By using transformer it becomes bigger one. So, only i need transformer less measurement.

I tried voltage divider method also. While we use voltage divider in 230 VAC, resisters become busted..

i attached, what circuit i have used for voltage divider.

check it and correct, otherwise suggest me any other measurement method.

 

[BoopathiRaja]

Hi.. IanB..

I tried your non isolated method.. i got 13V Dc output.

I will try to implement this method for my application.

Thanks.

 

[IanP]

You can consider several variations of that circuit, for example, if you prefer to keep the same level for [N] and [0V] then replace the bridge with just one diode .. see attached picture ..

IanP

 

[Enlightenment]

This might give you some ideas.

1976 Patent 3962631 Circuit for determining a measure value of a rectified AC voltage:
https://www.freepatentsonline.com/3962631.pdf

 

[pranam77]

Hi.. IanB.. I tried your non isolated method.. i got 13V Dc output. I will try to implement this method for my application. Thanks.

Yes..you'll have to fine tune the divider network to get a volatge below the PIC's safe level to protect the PIC. Guess this method suggected by "IanP" will work fine. But remember that it is non isolated...Cheers

 

[rrudman]

Here is a fairly robust/safe method of doing it. I used it for a Automatic transfer switch a while ago. The trick is to attenuate the signal enough so you can still measure it.