how to detect current intensity from a AC line.

[abhishekdixit]

hello, i have an AC line from which current is flowing, and the intensity of the current is varying simultaneously, now my problem is dat i hav to connect that variation with the LED bar graph, when the intensity of current varies, it displays on led bar graph by blinking led, now i am unable to understand how should i do this??
thanx


with regards,
Abhishek Dixit

 

[chuckey]

LED bar graphs respond to a voltage input. You need something to sense the AC current. One device is a Hall effect IC, this will give a variable output depending on the magnetic field, so if it placed in close contact with a single in your AC line, the field due to the current will operate it. Anther technique is to use a current transformer. This is a dough nut device through which the current carrying conductor passes. The transformer will produce a small isolated voltage output which can then amplified and used to drive your bar graph IC.
Frank

 

[abhishekdixit]

hello chuckey,
thans for the help, please can you suggest me any particular hall effect IC, on which you have worked or you know about it. so please refer me...

 

[abhishekdixit]

hiiiii,
can their is any other way to convert to AC to DC which is used for drive led bar graph..

 

[Gimlix]

I think you should install a Hall effect sensor around your AC line. Here you have lots of them:

https://uk.farnell.com/jsp/search/browse.jsp?N=203849&No=0&getResults=true&appliedparametrics=true&locale=en_UK&divisionLocale=en_UK&catalogId=&skipManufacturer=false&skipParametricAttributeId=&prevNValues=203849&filtersHidden=false&appliedHidden=false&autoApply=false&originalQueryURL=%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D203849%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK%26divisionLocale%3Den_UK%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D203849

You must choose the right one depending on the physical diameter of your cable, the maximum Irms you want to senes, and the kind of output you are looking for (0-5V, 0-10V, 4..20mA, etc.).

If you take, for instance, a 0-5V output, then you should add an instrumentation op-amp to make your signal addequate for your purpose and then drive the LED bar.