Hello.
The impedance is expressed as Z = R + iX where R is a resistance and X is a reactance.
Since R can not be negative, angle of Z, θ in Z = exp(iθ), must be within [90°, -90°] for any impedance, right?
However, when I naively measured a voltage and current at a point on RF circuit by using HV (High Voltage) probe and CT (Current Transformer), θ derived from these profiles is ~ 187°. RF signal frequency is 13.56 MHz. I'm guessing that a signal propagation time from the HV probe to an Oscilloscope is different from that for the CT, so this unrealistic impedance angle is measured.
Could you tell me whether or not I'm right? If I'm not right, could you give me possible causes for this wrong measurement?
The impedance is expressed as Z = R + iX where R is a resistance and X is a reactance.
Since R can not be negative, angle of Z, θ in Z = exp(iθ), must be within [90°, -90°] for any impedance, right?
However, when I naively measured a voltage and current at a point on RF circuit by using HV (High Voltage) probe and CT (Current Transformer), θ derived from these profiles is ~ 187°. RF signal frequency is 13.56 MHz. I'm guessing that a signal propagation time from the HV probe to an Oscilloscope is different from that for the CT, so this unrealistic impedance angle is measured.
Could you tell me whether or not I'm right? If I'm not right, could you give me possible causes for this wrong measurement?