I would like to measure AC power consumption of devices such as AC/DC charger, AC LED bulb or an electric circuit in the main box of a house.

However, their power consumption are quite low and the cosinus phi is not always usable to compute power consumption while this kind of devices does not have a proper sinus wave form.

How can I measure such consumption? Currently I have AC/AC adapter to have the voltage measurement and a clamp on amperemeter for the current. But I need to perform some calculations to determine the true power.

How can I do that? Is there a dedicated MCU or can I perform this with an oscilloscope?

  • \$\begingroup\$ Do all devices cause a phase lag? Simple incandescent lights for example? \$\endgroup\$ – Solar Mike Feb 26 '19 at 6:20
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    \$\begingroup\$ Youtuber BigClive: youtube.com/channel/UCtM5z2gkrGRuWd0JQMx76qA uses a HOPI for that: nl.aliexpress.com/item/… sure you could also use an oscilloscope to measure this but that's complicated, you would need an (isolated) high voltage probe and a current transformer or such. The HOPI is a much simpler solution. \$\endgroup\$ – Bimpelrekkie Feb 26 '19 at 7:34
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    \$\begingroup\$ What kind of accuracy do you need? \$\endgroup\$ – winny Feb 26 '19 at 8:35
  • \$\begingroup\$ @Bimpelrekkie You shouldn't answer questions in the comment field. \$\endgroup\$ – pipe Feb 26 '19 at 8:48
  • \$\begingroup\$ I need a accuracy for low power consumption of about 0.2 W. I appreciate the aliexpress solution but i need the 8173 version if i understand. I dont see any accuracy. Have you got an idea? \$\endgroup\$ – Ksartor Feb 26 '19 at 9:55

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