Impedance Laboratory

DC and low frequency impedance measurements are performed in the Impedance Laboratories. Impedance Laboratories are divided into two divisions, namely: the DC Resistance Laboratory and the Capacitance Laboratory. The services provided by these laboratories and their work areas can be summarized as follows:


The traceability of DC resistance measurements is to the Quantum Hall Resistance Standard established at TÜBİTAK UME, and the traceability of AC resistance measurements is provided by calculable AC resistors. Inductance measurements are performed at the primary level using a Maxwell-Wien Inductance Measurement Bridge, while capacitance standards are calibrated by the BIPM.

DC resistance measurements can be performed between 100 µΩ and 100 TΩ. DC resistance measurements between 1 GΩ and 100 TΩ are performed using a TÜBİTAK UME made Wheatstone Bridge, while measurements up to 1 GΩ are performed using commercially available measurement bridges. Low current measurements down to 2 pA can also be performed using high value resistors. Studies to extend the scope of the low current measurements below 2 pA are being carried out.


The traceability of AC resistance measurements is obtained by means of calculable AC resistors whose DC values are traceable to the Quantum Hall Resistance Standard. AC resistance measurements are usually used for calibrations of RLC meters. These measurements are performed in the range between 10 Ω and 2 MΩ at TÜBİTAK UME.

The traceability of capacitance measurements are obtained via Fused-Silica capacitors that are calibrated by the BIPM. Two commercial bridges, AH2500A and AH2700A are used for the capacitance calibrations up to 1 µF. Capacitance calibrations between 1 µF and 1 mF are performed using a TÜBİTAK UME made capacitance measurement bridge. Capacitance measurement frequency is up to 30 MHz for Agilent 16380 type capacitors.

The traceability of inductance measurements is obtained from capacitance and AC resistance units using a Maxwell-Wien Bridge established at the laboratory. While the inductance measurement range is 100 µH - 10 H, inductance measurements of the order of nH can be performed thanks to recent developments in the laboratory.

AC voltage ratio measurements are generally used for inductive voltage dividers and strain gauge indicators/calibrators. The traceability of AC voltage ratio measurements are provided by a TÜBİTAK UME-made primary level inductive voltage divider calibration system.

In addition to calibration services, device and standard manufacturing services are also provided in the Impedance Laboratories. Devices and standards such as DC resistance standards, current shunts, capacitance standards and inductive voltage dividers can be manufactured in the laboratory.