Simple and low cost wattmeter for AC 220V 60Hz

Discussion in 'General Electronics Chat' started by toninph, May 1, 2012.

  1. toninph

    Thread Starter New Member

    Dec 10, 2010
    I am triggered and irritated by the fact that wattmeters are not available in my country (Philippines). So I'm looking to build a simple one myself. I'm on 220V 60Hz. Except for two aircon outlets, all outlets are two pronged-non-polarized thus without ground. The wattmeter does not need to be super precise. I neglect power factor. I intend to measure measure power consumption outlet by outlet, appliance by appliance. Right now, I'm not into microprocessors and wireless (yet).
    The devices/schematics I saw so far require neutral/live/ground. Here is one I like, because it is simple by using an AD633 (skip the advertisement):
    And here:
    I spent the best part of the day looking for more information, including here, but to no avail. I hope I can find advice here.
    Does anyone have experience with these circuits? Is it possible to make it safer, solve the neutral/live/ground issue by using a current clamp or optocouplers?
    Note: the Philippines has the highest electricity cost in Asia and 5th highest in the world. I'm in dire need to understand my power usage!