The goal is to catch an AC leak. For these purposes, I use a measuring transformer (RCMB121). When there is no leakage, the output contacts are low (GND). If an accident occurs, the contacts go into a high impedance state. How can I read high impedance condition with Arduino Uno? As I understand it, this is not a HIGH level. Can I pull these contacts resistors (10k) to the power line?


1 Answer 1


If you mean "power line" as in the 5V rail, then yes. Page 3 in the datasheet:

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High impedance means the output is floating in that state, so it's your own job to pull it (UP in this case) to the right voltage which your circuit understands as a HIGH/LOW.

  • \$\begingroup\$ Linkyyy, So I just need to pull these contacts to + 5V and I can read the HIGH state during high impedance? \$\endgroup\$
    – Delta
    Dec 7, 2018 at 10:30
  • \$\begingroup\$ @АлексГарисон: Yes \$\endgroup\$
    – Linkyyy
    Dec 7, 2018 at 13:20

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