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What happens if we measure 220V AC from wall socket with a multimeter in DC mode (instead of AC)?

If I remember correctly, it should show the average value of this sinusoidal 220V, i.e. 0V.

Is this true with nearly all multimeters?

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    \$\begingroup\$ depends on how fast the meter performs the measurement. If only 1 millisecond, the meter may show a PEAK value, either -220volt or +220 volt. Or halfway down the sinusoid, perhaps at 45 degrees where 70.7% is an estimate, and 70.7% of 220 is 154 volts. \$\endgroup\$ – analogsystemsrf Oct 25 '19 at 10:53
  • \$\begingroup\$ Typically it should/would show 0V. But/and, as this is a non standard use "anything MIGHT happen". Why do you ask? \$\endgroup\$ – Russell McMahon Oct 25 '19 at 11:05
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    \$\begingroup\$ @RussellMcMahon Just out of curiosity: I was wondering if there was a system to prevent noobs from doing "Let's measure this wall socket. Ok, multimeter ON, voltage measurement, OK. Humm 0V, it's ok I can touch with my fingerrrrrrshkjshuidirhyuezhihfishdfijs^@$^!$^$ \$\endgroup\$ – Basj Oct 25 '19 at 11:41
  • \$\begingroup\$ @Basj ..Very many True RMS meters accept only AC (they block DC). I'd suggest a lawyer representing a burnt noob could make a shambles of that meter manufacturer. A few meters include DC and make a proper RMS measurement that should help your concerns. \$\endgroup\$ – glen_geek Oct 25 '19 at 13:39
  • \$\begingroup\$ " I was wondering if there was a system to prevent noobs from doing ..." There is no fool proof solution, which is the reason why noobs should stay away from line voltages. "Against stupidity the gods themselves contend in vain. " \$\endgroup\$ – Oldfart Oct 25 '19 at 16:26

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