Efisien[PU1]  daya solar tracker  masih sekitar 8,87%, telah banyak dikembangkan bahan panel surya maupun posisi letak panel surya dalam menangkap sinar matahari. Penggunaan solar tracker cukup dikenal  namun belum digunakan secara masif[PU2] , karena tipe tracker membutuhkan energi tambahan untuk menggerakkan modul surya sepanjang hari, dikhawatirkan justru akan menghabiskan energi listrik yang dihasilkan modul surya. Penelitian ini membuat prototype solar tracker dengan mengatur waktu penggerakan modul surya untuk dapat menghasilkan energi total lebih besar dibandingkan modul surya tipe statis. Prototype ini menggunakan papan Arduino Mega 2560 sebagai pengendali dan 4 sensor cahaya LDR (Light Dependent Resistor), digunakan  untuk penyimpanan modul surya  secara otomatis[PU3] , dan 3 motor stepper. Energi total yang dihasilkan dengan tracker sebesar 116383 Joule per jam lebih besar dari energi tipe statis sebesar 103038 Joule per jam. Rata rata rasio efisiensi energi solar dinamis versus energi solar sel statis sebesar 12,95 %, proses penyimpanan modul surya secara otomatis[PU4]  saat tidak ada sinar matahari untuk memperpanjang masa pemakaian panel surya.

Bismuth ferrite (BiFeO3) is one of multiferroic material group, but it is difficult to produce BiFeO3 in single phase as multiferroic material because it occurs leakage of current arising from non stoichiometric. So, to minimize it, it has already been engineering processed to synthesis BiFeO3 doped by Mg to produce Bi0.9Mg0.1FeO3 and Bi0.93Mg0.07FeO3. It used sol-gel method to produce the ceramics. The result of TGA/DTA(Thermo Gravimetric Analysis/Differential Thermal Analysis) test shows that the temperature of calcination is about of 150 and 175oC and temperature of sintering is about of 650oC. Characterization of the powder has already been done by using X-Ray Diffraction (XRD) test and electrical properties test. The results of XRD test show that the powder of Bi0.9Mg0.1FeO3has minimum impurities with total oxide of 6.9% (bismite 3.5% and silenite 3.4%) at calcination temperature of 175oC for 4 hours and sintering at 650oC for 6 hours. Meanwhile at same parameter, Bi0.93Mg0.07FeO3 has more oxide phases with total oxide of 14.5% which consists of silenite (2.5%) and Bi2O4 (12%). Presence of oxide phases could cause leakage of current decreasing electrical properties. The values of electrical saturation polarization for ceramic having minimum total oxide (Bi0.9Mg0.1FeO3) is higher than ceramic having more oxide (Bi0.93Mg0.07FeO3). The value of electric saturation polarization for Bi0.9Mg0.1FeO3 is of 0.26 kv/cm and for Bi0.93Mg0.07FeO3 is of 0.11 kV/cm.

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To introduce young people at school at early stage to engineering profession, an activity such as giving a lecture and some demo to them becomes important. This activity will hopefully create better understanding on engineering world especially in the field of electrical engineering by introducing an increasingly popular technology called IoT (Internet of Things). The target school is SMK Muhammadiyah 02 Tangerang Selatan. Because of COVID-19 pandemic situation and PSBB rules implemented in Tangerang Selatan in which school students had to study from home, then the lecture was given online by Zoom application on Tuesday, August 18th at 13.30 – 15.00 WIB. The partcipants attending the online lecture reached 26 consisting of grade III students of Computer Network program and some teachers as well. The results of the questionnaires given shortly before the webinar ends show that for Introduction of Engineering Profession, the majority of them (61,54%) states Interesting Enough, for Introduction of IoT the majority (57,69%) says Interesting and for IoT Demo the majority (53,85%) thinks Interesting Enough. The benefit of this webinar is clear when the majority of participants (57,69%) agrees Beneficial to them and all of them (100%) say Agree that this activity is also introduced to other students at school

The need for electricity has increased every year. One of the most popular supply of electrical energy is electrical energy from energy sources flowing and plunging water, called as the Micro Hydro Power Plant (PLTMH). Cisadane River is one of the major rivers with length around 80 kilometers and crosses 44 districts in 5 regencies / cities, including desa Kranggan, South Tangerang. Therefore, community service is carried out in an effort to utilize and optimize the flow of the Cisadane river. The Study of PLTMH design for community service program was conducted. Data of river flow, altitude and location of the river flow will be collected so that it can be calculated and observed for the design of PLTMH that best suits the efficiency of the largest electrical energy, which is obtained using the TurbinPro software program. PLTMH planning chose to use a propeller/kaplan turbine because of its low head which is 4 meters. The power generated is 994 kW at a maximum head with an efficiency of 91.2% and a river flow of 52.26 m3/s and at a minimum head of 601 kW with an efficiency of 82.2% and a discharge of 47.56 m3/s. Keywords: electrical energy, community service program, PLTMH, power generation, Kaplan turbine