Free Resistor Research Articles

The Charge Non-Conservation Paradox Implied by Loss Free Resistors

The Charge Non-Conservation Paradox Implied by Loss Free Resistors

UJI AKTIVITAS ANTIOKSIDAN EKSTRAK GANGGANG HIJAU (Ulva lactuca L.) DENGAN VARIASI KONSENTRASI PELARUT ETANOL 60%, 75%, DAN 96% MENGGUNAKAN METODE DPPH (1,1-difenil-2-pikrilhidrazil)

Free radicals give a negative effect. According to earlier research, Spyrogyra and Ulva lactuca L. have an anti-oxidant activity. This research aim to knowing the extract potential of green algae (Ulva lactuca) with variety concentration solvent as anti-oxidant by DPPH method, and finding the price of IC50 ethanol extract which compared with Galat acid. Extraction technic was maseration with ethanol solvent 60%,75%, and 96% which is implemented a qualitative test of extract active compound of U. lactuca Antioxidant activity of U. lactuca extract measured with spektrofotometri by using DPPH (1,1-difenil-2-pikrilhidrazil) method to get percentation of free radical resistor. The analytical result using SPSS, statistically got 95% credibility (p=0,05). This research showed that activity of antioxidant ethanol extract 96% of U. lactuca was higher than ethanol extract 60% and 75%. Activity of antioxidant ethanol extract 60%,75%, and 96% which confirmed by value of IC50 continously are 441,70 mg/ml ; 242,10 mg/ml dan 2,04 mg/ml. Whereas the value of IC50 galat acid standard is 3,92 x 10-3mg/ml. Based on tests of conducted antioxidant activity, the gallic acid has a strong antioxidant power, U. lactuca have a very weak antioxidant power

Emulation of Loss Free Resistor for Single-Stage Three-Phase PFC Converter in Electric Vehicle Charging Application

In this article, the modular three-phase ac-dc converter using single-phase isolated Ćuk rectifier modules for charging of electric vehicles is discussed. The converters are designed and analyzed for the continuous conduction mode (CCM). This article is based on a new concept of adaptive sliding-mode-based loss-free resistor (ASLFR). ASLFR is a control scheme, which allows dual aim of power factor correction along with tight voltage regulation; hence, the adopted topology serves as a fitting single-stage solution for balanced three-phase systems. Complete theory is developed for the application, and the effectiveness of the scheme is well-established. Various studies to confirm the robustness of the system to any load and line variation are carried out. Moreover, a qualitative analysis is also made to show the expediency of the proposed ASLFR. Simulation as well as experimental studies are claimed theoretically.

Analysis of Sliding-Mode Controlled Impedance Matching Circuits for Inductive Harvesting Devices

A sea-wave energy harvesting, articulated device is presented in this work. This hand-made, wooden device is made combining the coil windings of an array of three single transducers. Taking advantage of the sea waves sway, a linear oscillating motion is produced in each transducer generating an electric pulse. Magnetic fundamentals are used to deduce the electrical model of a single transducer, a solenoid-magnet device, and after the model of the whole harvesting array. The energy obtained is stored in a battery and is used to supply a stand-alone system pay-load, for instance a telecom relay or weather station. To maximize the harvested energy, an impedance matching circuit between the generator array and the system battery is required. Two dc-to-dc converters, a buck-boost hybrid cell and a Sepic converter are proposed as impedance adaptors. To achieve this purpose, sliding mode control laws are introduced to impose a loss free resistor behavior to the converters. Although some converters operating at discontinuous conduction mode, like the buck-boost converter, can exhibit also this loss free resistor behavior, they usually require a small input voltage variation range. By means of sliding mode control the loss free resistor behavior can be assured for any range of input voltage variation. After the theoretical analysis, several simulation and experimental results to compare both converters performance are given.

Adaptive Sliding Mode Based Loss-Free Resistor for Power-Factor Correction Application

The emulation of virtual resistance finds various applications in the power processing industry. This paper proposes a novel notion of adaptive sliding mode based loss free resistor (ASLFR). This is achieved by allowing the input power of the power-out power-in ( POPI ) system to vary, in order to accommodate the load demands. In this paper, the concept is illustrated for power-factor correction (PFC) applications. The ASLFR is used to achieve the dual purpose of harmonics-free rectification along with excellent system response under load and line transients. The scheme serves itself as an efficient single-stage PFC solution. A generic mathematical formulation of the scheme is presented, which can be used for different converters. Then on, a boost topology, operating in continuous conduction mode, is chosen to demonstrate theoretical developments and to showcase the effectiveness of the scheme. The robustness of the proposed controller to any line or load variation is established. A fast voltage recovery with almost no undershoot/overshoot is achieved at transients by using the proposed controller. Additionally, a qualitative analysis is provided to demonstrate the expediency of the proposed ASLFR. The theoretical claims are well supported by simulation as well as experimental results.

Multicell Three-Phase AC–DC Driver for HB-LED Lighting Applications

High-brightness light-emitting diodes (HB-LEDs) are becoming omnipresent across all aspects of illumination products, due to their incredible characteristics such as efficiency, reliability, long lifetime, controllability, etc. This paper proposes power conversion topologies to drive medium to high power HB-LEDs in three-phase power grids when these connections are available. For that reason, an evaluation of several drivers for medium to high power HB-LEDs in three-phase power grids is done. Moreover, a new topology is proposed, which complies with IEC 1000-3-2 Class C requirements, achieves high power factor, low total harmonic distortion, and the capability to have a flicker free behavior while disposing of the bulk capacitor and having galvanic isolation. The HB-LED driver is based on a modular approach with several cells working together with their inputs connected to the three-phase network and their outputs connected in parallel generating a dc output. Each one of these cells is a dc–dc converter operating as a loss free resistor. In order to validate the concept, a prototype has been built by the use of flyback converters operating in discontinuous conduction mode. Furthermore, it operates in the full range of the European three-phase line voltage, which varies between 380 and 420 V, and it supplies an output voltage of 48 V with maximum power of 90 W.

Microstructure and electrical performance of eco-friendly thick film resistor compositions fired at different firing conditions

Perovskite ruthenates, viz. CaRuO 3, SrRuO 3, BaRuO 3, etc. although exhibit many interesting physical properties, have been seldom used in thick film resistors. In the preliminary attempts, we have formulated lead free thick film resistor paste compositions using CaRuO 3. Five different paste compositions by varying the ruthenate concentration were prepared. Thick film resistors were screen printed onto an alumina substrate. Different thick film firing conditions were adopted to fire the resistors. Although, for TFRs, the standard conventional firing cycle is 850 °C, our TFR compositions can be fired even at a peak temperature of 800 °C. The evolution of microstructure and electrical performance of these resistors were studied. The resistors fired in conventional thick film firing furnace (BTU make) were found to be morphologically more uniform than the resistors fired in normal tube furnace. However, the sheet resistance value ‘ R s’ is lower (54–1.36 kΩ/□) in case of resistors fired in tube furnace. On the other hand, resistors fired in thick film firing furnace exhibit higher range of sheet resistance (1.36–800 kΩ/□). The hot and cold TCR range is 180–560 ppm/°C in case of tube furnace fired resistors and 120–235 ppm/°C for BTU furnace, which is comparatively lower than those reported earlier (>600 ppm/°C) for other lead free resistors.

Investigation of basic elements and devices in multilayer technology for HTS digital RSFQ circuits

Abstract Complex high temperature superconductor digital RSFQ circuits require a multilayer technology that is compatible with freely positionable Josephson junctions. For RSFQ circuits, especially small inductances are required. This can be achieved by using superconducting striplines on a YBCO groundplane. We have produced and examined all basic elements like, e.g., superconducting cross-overs, vias, pinhole free insulation layers and on-chip resistors that are necessary to design and fabricate HTS RSFQ circuits. All structures have been successfully tested and integrated with ramp type junctions with PBCO barriers. For the superconducting lines over the groundplane an inductance of 0.8 pH/square was measured which shows the advantage of a superconducting groundplane. Based on this technology we fabricated a simple multilayer circuit consisting of two magnetically coupled d.c.-SQUIDs. Here we used bicrystal junction stacks due to the smaller spread of junction parameters. The circuit allowed essential operations like generating, erasing and detecting a single flux quantum. One d.c.-SQUID served as storage loop while the other was kept permanently in the voltage state and was used to determine the internal flux state of the storage loop.

Transmission line based energy recovery circuits and their application in copper vapor laser systems

Energy recovery of narrow, high power pulses based on loss free resistor topology is described. A novel regenerative snubber realization based on transmission lines is presented. The purpose of this snubber is to recycle high voltage, high power (up to 20 kV 1 MW) parasite pulses which arise in a copper vapor laser. These pulses consume up to 40% of the total power of the system. Currently, a low voltage (170 V) circuit of this type has been constructed and operated at recycling efficiency up to 85%.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>