Asep Nugroho
Pusat Tenaga Listrik dan Mekatronik LIPI Jln. Cisitu Lama, Dago, Bandung.

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PENINGKATAN KETERAMPILAN MENGKOMUNIKASIKAN DAN INFERENSI MELALUI MODEL PEMBELAJARAN INKUIRI TERBIMBING Nugroho, Asep; Diawati, Chansyanah; Kadaritna, Nina
Jurnal Pendidikan dan Pembelajaran Kimia Vol 2, No 2 (2013): Jurnal Pendidikan dan Pembelajaran Kimia
Publisher : Program Studi Pendidikan Kimia FKIP Unila

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Abstract

This research is intended to describe the effectiveness of guided inquiry learning model applied in acid and alkali subject to improve students’ presentation and drawing inference skill.  This research used Pre-experimental method by one-group pretest-posttest design.  The subjects of this research are the second semester students of class XI IPA 1 SMA Muhammadiyah 2 Bandar Lampung in academic year 2012-2013.  The effectiveness of guided inquiry learning model showed by the increase of pretest and posttest scores that can be seen by the n-Gain value.  The result showed that n-Gain value average of students’ presentation skill is 0,45 and the students ‘drawing inference skill is 0,39.  It can be conclude that guided inquiry learning model applied in acid and alkali subject is effective in improving students’ presentation and drawing inference skill in medium criteria.Penelitian ini dilakukan untuk mendeskripsikan efektivitas model pembelajaran inkuiri terbimbing pada materi asam-basa dalam meningkatkan keterampilan mengkomunikasikan dan inferensi.  Penelitian ini menggunakan metode pre-experimental dengan One-Group Pretest-Posttest Design.  Subjek dalam penelitian ini adalah siswa kelas XI IPA1 SMA Muhammadiyah 2 Bandar Lampung semester ganjil tahun ajaran 2012-2013.  Efektivitas model pembelajaran inkuiri terbimbing ditunjukkan oleh adanya peningkatan nilai pretest dan posttest yang dilihat dari nilai n-gain.  Hasil penelitian menunjukkan bahwa rata-rata nilai n-gain keterampilan mengkomunikasikan sebesar 0,45 dan keterampilan inferensi sebesar 0,39.  Dapat disimpulkan bahwa pembelajaran inkuiri terbimbing pada materi asam-basa efektif dalam meningkatkan keterampilan mengkomunikasikan dan inferensi dengan kriteria sedang.Kata kunci: inferensi, keterampilan mengkomunikasikan, pembelajaran inkuiri terbimbing.
Buck Converter Control for Lead Acid Battery Charger using Peak Current Mode Nugroho, Asep; Rijanto, Estiko; Rozaqi, Latif
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 8, No 2: June 2017
Publisher : Institute of Advanced Engineering and Science

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Abstract

DC-DC buck converters are used for battery chargers in many applications including renewable energy sources, inverters, electric vehicles and robots. In this paper a buck converter was built and its controller was developed using peak current control mode for current loop and phase lag for voltage loop. This paper proposes a formulation of plant disturbance due to load variation to obtain a nominal model based on small signal approach. The controller was derived analytically based on the nominal model. Experiment results show that the buck control system functions well in regulating the output voltage. During the start up without any load it can reduce input voltage from 300 V to output voltage of 133.9 V in 19.3 ms. The developed controller can maintain the output voltage under load variation from no load to sudden load of 0.26 A. When it was implemented to charge a lead acid battery string, constant current of 3.36 A was charged in the first 173 minutes followed by constant voltage of 134.7 V until the end of charging at time 483 minutes. Thus, the developed control system of lead acid battery charger works well.