AC voltmeter

Other Hardware Sensors
1

Hi guys,

I'm looking for a sensor or something to measure AC voltage (210-270V AC).
Do you think that I can use a bridge rectifier to convert from AC to DC and a voltare divider to reduce the voltage to 0-5V to use with Analog input. Maybe using an optoisolator to protect my arduino..

I don't have enought electronics knowledge to do that.. :slight_smile:

Thank you :slight_smile:

2

--->Warning! Lethal voltage present!<---

I would consider something like the LTC1966 for this application. You would need about 800:1 transformer.

3

A safe way to measure household AC voltage is described here.

4

How accurate do you need the measurement to be?
Having to go up to 270V makes the task quite difficult, as the traditional approach of using a mains transformer
and measuring the secondary voltage wont work properly,as the transformer will be core saturating with 270 V into it, and the secondary voltage will be incorrect.

5

I just check the article provided by jremington, the idea is not bad, just put an adapter to reduce the voltage, but I need a "non stable" adapter.

I just found that from my supplier website, how do you think? It is an AC to DC unregulated adapter, it mean i just need a divider to reduce the voltage under 5v for arduino analog pin..

http://intronic.ch/franz/produkte/pdf-neu/07A_002f.pdf

Thank u guys :slight_smile:

6

mauried:
How accurate do you need the measurement to be?
Having to go up to 270V makes the task quite difficult, as the traditional approach of using a mains transformer
and measuring the secondary voltage wont work properly,as the transformer will be core saturating with 270 V into it, and the secondary voltage will be incorrect.

I just check and for now is enough to measure 235 VAC +-10%, so i think a normal transformer will be ok, about the precision 0.1v is good.

thanks :slight_smile:

7

It is an AC to DC unregulated adapter

This won't work well, as it returns a voltage proportional to the peak value of the AC line, which can include noise. Use an AC to AC adapter, as the article describes.

8

jremington:
This won't work well, as it returns a voltage proportional to the peak value of the AC line, which can include noise. Use an AC to AC adapter, as the article describes.

Something like that? That supplier sell directly a 9VAC version that's exactely what they use in the article :slight_smile:

http://intronic.ch/franz/produkte/pdf-neu/15A_002f.pdf

9

I was thinking more people would reply~~~ :frowning: