I have to measure AC voltage of the mains supply 180-220 VAC through a microcontroller. I have been wondering how to measure it without using a voltage divider. Since the resistance may wear out with time, doesn't sound like a good design.
I can use a transformer but that design would be too bulky. Isn't there any other way? Even the voltage sensing IC's use a resistive network to divide the voltage.
Best Answer
More sane/safe solutions typically use linear (high linearity) optocoupler, which provides several kilovolts of isolation. But designing with these is not exactly a piece of cake. Here's an article on one such design: http://www.edn.com/design/test-and-measurement/4344950/Optocoupler-simplifies-power-line-monitoring (note this for 110VAC, but can be probably be adapted for 230VAC with some care.)