I want to measure household voltage...that is about 200V - 250V AC

I saw this project with the ADC IC ICL7107 here

but the problem is this measures DC voltage....

Please suggest me how will i measure the 250V ac current....???

 

The ICL7107 is a DC voltmeter chip. Do you have any electronic skills? We have to know, as dealing with line voltage is quite dangerous. You will need to be able to assemble small parts on a board and house them all in an insulated case.

A very inexpensive DVM will do what you want. It will cost less than the parts to make your ICL7107 safe to measure AC.

 

yes i do have electronic skills...
Actually i want to add two of these voltmeters on the input and output of a 1kv 220volt step up transformer and monitor it all the time....

 

Then look for an AC voltmeter IC, instead of using a DC one....

Or buy a DVM, you can still look at the display and "monitor" those lines..... some DVM even have a sample and hold function, and some can interface to a PC for data collection.

B. Morse

 

and moreover i want to use the seven segment display so that it is visible from a little far all the time...

 

You don't say where you live, but if you're in the US, Harbor Freight (and others) sell little digital multimeters for less than $10 (I've seen them on sale for $4 in the local store). You could use two of these and a wall wart and be up and running in very little time.

 

yes I am from INDIA...here we have cheap DVM too...i surely can use them ...But the problem is they all use LCD which u cannot see from lil far or at night in a glance...
That is the reason i wanted to use the seven segment display...

 

You can find very inexpensive DVM's with LED backlighting.

I have a couple of these: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92020
They frequently go on sale for $4 or $5 USD (227ru to 284ru)
The LED backlight makes them very visible for a reasonable distance.