TY - JOUR N2 - Noise spectroscopy and I-V characteristic non-linearity measurement were applied as diagnostic tools in order to characterize the volume and contact quality of positive temperature coefficient (PTC) chip sensors and to predict possible contact failure. Correctly made and stable contacts are crucial for proper sensing. I-V characteristics and time dependences of resistance were measured for studied sensors and, besides the samples with stable resistance value, spike type resistance fluctuation was observed for some samples. These spikes often disappear after about 24 hours of voltage application. Linear I-V characteristics were measured for the samples with stable resistance. The resistance fluctuation of burst noise type was observed for some samples showing the I-V characteristic dependent on the electric field orientation. We have found that the thermistors with high quality contacts had a linear I-V characteristic, the noise spectral density is of 1/f type and the third harmonic index is lower than 60 dB. The samples with poor quality contacts show non-linear I-V characteristics and excess noise is given by superposition of g-r and 1/fn type noises, and the third harmonic index is higher than 60 dB. L1 - http://www.journals.pan.pl/Content/90198/PDF/Journal10178-VolumeXX%20Issue4_10.pdf L2 - http://www.journals.pan.pl/Content/90198 PY - 2013 IS - No 4 EP - 644 DO - 10.2478/mms-2013-0054 KW - PTC chip sensors KW - noise spectroscopy KW - I-V characteristic non-linearity KW - quality evaluation A1 - Grmela, Lubomír A1 - Sita, Zdenek A1 - Sedlakova, Vlasta A1 - Majzner, Jiri A1 - Sedlak, Petr A1 - Sikula, Josef PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation DA - 2013 T1 - Analysis of Noise and Non-Linearity of I-V Characteristics of Positive Temperature Coefficient Chip Thermistors SP - 635 UR - http://www.journals.pan.pl/dlibra/publication/edition/90198 T2 - Metrology and Measurement Systems ER -