Browsing by Author "Setiadi, Rahmondia N."

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    PEMBUATAN ALAT UKUR KUAT MEDAN MAGNET INDUKSI BERBASIS KOMPUTER
    (2013-03-05) Gusrini, Elni; U., Lazuardi; Setiadi, Rahmondia N.
    Magnetic field is an important physical quantity in many research fields such as research in geology, geophysics, and research in the field of magnetism. In this paper, a computer-based instrument for measuring induced magnetic field strength is decribed. The instrument system for measuring magnetic field strength is an instrument with an external measuring unit using KMZ10B magnetoresistive sensor with analog amplifiers controlled by an ADC 7822 microprocessor, and connected to host personal computer with running application software based Visual C++ for data acquisition. Based on various coil dimension and excitation currents, the system can be configured during the measurement. Induced magnetic field strength can be detected by measuring the inductance of the inductive coil in the vicinity of the position sensor. The instrument has been tested and calibrated using a standard calibrator of magnetic field instrument Teslamater FH51. A linier model based on the transfer function is used to convert and to evaluate the sensor output. Measurements with constant and variable current have been made at the center of solenoid as well as on the end of the solenoid resulting maximum field strength of BC = 1,51mT and BE = 1,23mT at the center and on the end of solenoids core respectively. The experiments show that magnetic field strength will increase with the number of coil winding and excitation current
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    Pembuatan Ec-Probe Untuk Mengukur Kelembaban Tanah Pertanian Mempergunakan Modifikasi Konfigurasi Wenner-Array
    (2013-03-05) Sinaga, Santon; U., Lazuardi; Setiadi, Rahmondia N.
    This study aims to create a soil moisture measuring device based on the Wenner method. The main circuit of the tool uses an IC a type LM 317A with output voltage 1.2 Volts to 37 Volts and can pass current of 1.5 A. The sensor used is a type of cylindrical electrodes with length of 705 mm and the detection electrode consists of a ring electrode with radius equal to 15 mm in diameter and 4 mm thick, spacerring and cone part can be opened. Testing soil moisture measuremen of Inseptisol that taken from UPT Faperta UR, Andisol from Bukittinggi and Entisol from area of watershed Kampar and measured using the calibrator Soil Tester Lutron produce five levels of soil moisture for each sample. Soil samples with moisture is tested and characterized with a modified 4- point Wenner by injecting a current of 1 mA. these modeling obtained a general mathematical equation model that describes the relationship between the electrodes voltage (UO) and soil moisture (θw) on the soil types Uo yo A Tw BTw2 CTw3 the equation is empirical and has different values for those three soil samples