This paper studies negative bias temperature instability in commercial IRF9520 p-channel power VDMOSFETs under both static and pulsed bias stress conditions in order to model this effect. The pulsed voltage stressing caused generally lower shifts as compared to static stressing performed at the same temperature with equal stress voltage magnitude, as a consequence of partial recovery during the low level of pulsed gate voltage. It was shown that the quantitative differences between static and pulsed NBT stress depend on the duty cycle, and the differences become more significant as the duty cycle decreases. It was found that 25 off-time of the pulsed stress voltage could suffice to remove the major part of the recoverable component of the degradation created during the foregoing pulse on-time. An equivalent electrical circuit has been proposed and on the basis of these experimental results a modeling of threshold voltage shifts induced by pulsed negative bias temperature stress has been done.

This paper reports the design of a photovoltaic energy harvesting device used as a telemetry node in wireless sensor networks. The device draws power from the small solar cell, stores it into the primary energy buffer and backup supercapacitor, collects measured data from various sensors and transmits them over low power radio link at 868 MHz. Its design ensures reliable cold booting under very poor illumination conditions (down to 20 $\mathrm{lx}$). The solar cell also enables indirect illumination level detection for the subcircuit that manages stored energy (day/night detector). The device is allowed to draw power from the backup supercapacitor only when it is not possible to gather enough energy from the solar cell during the sleep period. Short lasting and sudden drops of the illumination do not activate the backup power supply. A wireless sensor node design is adjusted to the proposed photovoltaic harvesting circuitry, so the overall power consumption in the sleep mode is less than 25 μW. Also, due to adaptive power consumption, proposed device topology ensures its autonomy time in the total darkness of 81 h$\mathrm{}$. The device has been produced using commercially available components enabling versatile telemetric functionality by the implementation of different sensors.

Contribution: Impact assessment of the practice-oriented course for high school students on their later academic achievements, described in the context of long-term efforts to improve electronic engineering studies’ quality. The article highlights the importance of outreach and extracurricular activities and cooperation with the IEEE in these efforts. Background: Faced with the practical application of theoretical knowledge, either in laboratory exercises or on small projects, students are not as successful as expected. A high school course promoting practical work has been developed, following the gathered experience and results from other studies. The intention was to track participants’ progress not only on the course but also during their later studies at the faculty. Intended Outcomes: Increased the number of proficient high school students enrolling in the university. Improved quality of papers at student conferences, organization of workshops and events attractive to students and educators, an increased number of young members of the IEEE. Impact on the policymakers. Application Design: In tailoring the course content, the goal was to mimic an engineering design cycle through project-based learning. In contrast to deductive learning, which students were accustomed to, assessment-based and active learning teaching strategies, such as think–pair–share, practical demonstrations through performance tasks, and homework practice, have been used. Findings: This research documents that students with practical experience in high school have more self-confidence and better university scores than those with none. The universities should step forward in initiatives to strengthen connections with high schools and professional societies.

This paper reports results of the transient modeling of thermoelectric cooling/heating modules as power generators with the aim to select preferable ones for use in thermal energy harvesting wireless sensor network nodes. A study is conducted using the selected commercial thermoelectric generators within the node of a compact design with aluminum PCBs. Their equivalent electro-thermal models suitable for SPICE-like simulators are presented. Model components are extracted from the geometrical, physical and thermo-electrical parameters and/or experimentally. SPICE simulation results mismatch within 7% in comparison with the experimental measurements. The presented model is used for the characterization of different thermoelectric generators within the wireless sensor network node from the aspects of harvesting efficiency, cold boot time, node dimensions and compactness, and maximum applicable temperature. The choice of the preferred generator is determined by its electrical resistance, the number of thermoelectric pairs, external area and thermoelectric legs length, depending on the primary design goal and imposed thermal operating conditions. The node can provide load power of 1.3 $\mathrm{m}\mathrm{W}$ and the cold boot time of 66 s for generator with 31 thermoelectric pairs at a temperature difference of 15 $°\mathrm{C}$ with respect to the ambient, and 7.6 $\mathrm{m}\mathrm{W}$ of load power and the cold boot time of 40 s for generator with 71 thermoelectric pairs at a temperature difference of 25 $°\mathrm{C}$ .

Autonomous energy harvesting sensors present one of the most attractive areas of microelectronics at the moment. They are a part of Internet of Things (IoT) systems so the data need to be protected across transmission. One way for data protection is encryption and the other way is digital signature. However, energy consumption of those systems is increased using protections algorithms, and it should be considered because these are energy harvesting systems. The paper describes the ways in which data encryption and digital signature algorithms can be implemented in resource limited systems based on an 8-bit microcontroller. Alongside the implementation method, the paper deals with the energy demands of the selected encryption algorithms and digital signatures. The execution time, energy consumption, and memory consumption will be considered.