In dielectric impedance measurement, what are the situations where the real part of impedance attains a negative value? Is it having any connection with a probable series resistance in an equivalent circuit? What are the physical contributions that gives raise to a series resistance effect? Can anybody help me figure this out. Thanks in advance.
Real part of the impedance cannot be -ve, it is positive........
Through out all frequencies is it negative or a particular frequency..?
U may aware about left handed materials...but that is only artificial.....
Error occurs due to series resistance that u mentioned.this is because of uneven electrode and high surface roughness of ur samples....... But that should only happen in the low frequency......different polarization mechanisms are dominate in the low frequency.......series resistance leads to more interfaces...so may be interracial polarizations.....u should consider the frequency also.....
Just Refere Prof. Grigas Books..Dielectric spectroscopy
Thanks for the response. It is not a ubiquitous issue. In a few measurements the first impedance arc started from a point that is a bit left to the zero real impedance. So I hope there is something slightly wrong in the sample holding or the sample geometry. So I am just curious what might that be.
Dear Vaisakhan Thampi
Switch on the equipment for recommended warm up time and then calibrate the equipment.Usually the standard calibration resistors of precision values will be supplied. Avoid calibration with the resistance given for some other made or make.The calibration resistor if it is dropped also will lead to erratic reading. .
For high precision impedance measuring equipment Standard open,standard short &standard impedance will be provided.Most of the experimenters just keep the probe open,short with crocodile clip with wires are common.which are wrong calibration procedures.
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