1
\$\begingroup\$

I want to compute the impedance of my system from measurements of the voltage and the current. Is it simply the ratio of the rms amplitudes of the voltage and current (Z = Vrms / Irms)?

\$\endgroup\$

1 Answer 1

3
\$\begingroup\$

No, that will give you the magnitude of the impedance. In order to get the full impedance you will also need to measure the phase shift between the voltage and current and combine that with the magnitude in order to get the phasor for the impedance.

\$\endgroup\$
1
  • \$\begingroup\$ Ok, that helps. Thank you. Clarifying question - what's the best way to measure the current? I currently use a current preamplifier, however it's dynamic range is not sufficient for my needs. Would using a resistor in series and then measuring the voltage across it be sufficient for obtaining a current measurement? If so, what value resistor would be optimal? \$\endgroup\$
    – Igoy
    Commented Jan 11, 2016 at 15:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.