FvM said:Are you re-scheduling your question because you don't like the answers you received? It's unwanted crossposting anyway.
FvM said:I think, the question should be better appended to the first thread. Anyway, the method I suggested as most economic is also considered the "best" in many fields of electrical engineering. But obviously, the criteria for "best" can be quite different, e.g. isolation safety, achievable overvoltage category, self-powered operation, bandwidth, phase error, amplitude error, size, temperature range, DC capability, required output signal and more.
bepobalote said:Rather strange as question: we even do not know where do you live!
There are LOTS of things to be taken in account before making such choice; some of them are:
1) how many pieces/year do you need
2) which certifications does your device require (UL, CE, BS, ...). Which safety norms do you must follow?
3) which circuit/method will you use to read the voltage and its precision/distortion/bandwidth requirements
4) min/max dimensions
5) max price/unit
6) Class of insulation and safety class of the transformer
Once you have answered to those questions, maybe we can be of some help.
Please remember that sometimes is cheaper to use custom products (ask to local transformer producers), sometimes it is better to buy ready made [COTS] components (see your typical local distributors: RS, Farnell, Digikey, Mouser, ...)
At this date your requirements are too vague to give you ANY answer.