Cuurent sensing question

 Hello I was looking at the page on current sensing Would not the use of a shunt resistor and voltage meter only be accurate if the phase shift between the current and voltage is zero. I would appreciate if somebody could explain this to me.


stephen's picture

Re: Cuurent sensing question

Current is out of phase with voltage in a reactive load (ie capacitive or inductive).  Where a current sensing resistor is in place (a non reactive element) the voltage across the resistor will be in phase with the current.  The voltage across the whole system may well be out of phase with the current (depending on the type of load) but that's not the same as the voltage across the sensing resistor.

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