Alpha-A Analyzer Measurement Examples:
High impedance materials and components
Some data are shown in terms of parallel resistance Zp' in Fig. 1 and parallel capacity Cp' in Fig. 2.
The crosses and circles show the results for two resistors components of 1011 Ω and 1012 Ω. The parallel resistance is Zp' flat and shows the expected value up to 3 Hz for the 1 TΩ resistor and up to 30 Hz for the 100 GΩ resistor respectively. At higher frequencies, the resistance decreases by about 3 orders of magnitude due to internal dielectric relaxation of the used resistor material. The measured capacity is nearly flat and around 200 fF for the 100 GΩ resistor and 100 fF for the 1 TΩ resistor. It is mainly due to the resistor wires and electrode stray capacities. The small capacity increase to low frequencies of 90 fF for the 100 GΩ resistor and 30 fF for the 1 TΩ resistor is due to the dielectric relaxation of the resistor material and consistent with the Zp' data.
The triangles show data of PVDF at −60 °C which is a high insulating dielectric material. The parallel resistance Zp' becomes especially at low frequencies extraordinary high, too. As for a dielectric material with not high losses expected, the capacity is nearly flat over the entire frequency range.
For comparison the squares show data of the open ZG4 impedance ports. These are the typical high impedance and low capacity instrument limits.