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Search results for: LOW-VOLTAGE CIRCUITS
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A 0.5-V bulk-driven voltage follower / DC level shifter and its application in class AB output stage
PublicationA simple realization of a 0.5-V bulk-driven voltage follower/DC level shifter, designed in a 0.18um CMOS technology is presented in the paper. The circuit is characterized by large input and output voltage swings, and a DC voltage gain close to unity. The DC voltage shift between input and output terminals can be regulated in a certain interval around zero, by means of biasing current sinks. An application of the proposed voltage...
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Time window based features extraction from temperature modulated gas sensors for prediction of ammonia concentration
PublicationElectronic gas recognition systems, in literature commonly referred as electronic noses, enable the recognition of a type and a concentration of various volatile compounds. Typical electronic gas-analyzing device consists of four main elements, namely, gas delivery subsystem, an array of gas sensors, data acquisition and power supply circuits and data analysis software. The commercially available metal-oxide TGS sensors are widely...
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Metody doboru miejsc zainstalowania zasobników energii w sieciach elektroenergetycznych niskiego napięcia
PublicationW związku z rosnącą liczbą źródeł odnawialnych przyłączanych do sieci niskiego napięcia (nn) jakość energii elektrycznej w tej sieci ulega pogorszeniu. Jedną z metod jej poprawiania jest instalowanie zasobników energii, tj. baterii akumulatorów, superkondensatorów czy kół zamachowych. Zasobniki energii są w stanie złagodzić dobową zmienność obciążenia, skompensować moc bierną i wyższe harmoniczne oraz zmniejszyć asymetrię obciążenia...
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STANY NIEUSTALONE TOWARZYSZĄCE POMIAROWI IMPEDANCJI PĘTLI ZWARCIA W OBWODACH WYJŚCIOWYCH ZASILACZY BEZPRZERWOWYCH UPS
PublicationW pracy przedstawiono metodykę i wyniki pomiarów stanów nieustalonych w zasilaczu bezprzerwowym (UPS) typu on - line. Do rejestracji zdarzeń po stronie zasilania i na wyjściu UPS wykorzystano dwa przyrządy do pomiaru jakości energii elektrycznej zsynchronizowane czasowo. Rejestratory kompresują uzyskane dane pomiarowe, co może wprowadzać dodatkowe błędy pomiaru wielkości mierzonych – napięć i prądów. Dodatkowe rejestracje oscyloskopem...
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Samotestowanie toru analogowego ze wzmacniaczem w pełni różnicowym w elektronicznych systemach wbudowanych sterowanych mikrokontrole-rami
PublicationPrzedstawiono nową metodę samotestowania toru analogowego opartego na wzmacniaczu w pełni różnicowym w elektronicznych systemach wbu-dowanych sterowanych mikrokontrolerami. Bazuje ona na nowej metodzie diagnostycznej opartej na przekształceniu transformującym próbki odpo-wiedzi czasowej badanej części analogowej na pobudzenie "ujemnym" impulsem prostokątnym na wejściu Vocm na krzywe identyfikacyjne w przestrzeni pomiarowej. Metoda...
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Detekcja i lokalizacja nieprzewodzenia tranzystorów falownika napięcia na podstawie analizy prądu obciążenia
PublicationPrzedstawiono nową metodę detekcji i lokalizacji nieprzewodzenia tranzystorów w falownikach napięcia zasilających silniki indukcyjne małej mocy. Metoda bazuje na monitorowaniu wartości dwóch sygnałów dia-gnostycznych. Pierwszy z nich, wskaźnik braku przepływu prądu, wykorzystano w celu detekcji uszkodzeń. Drugi, stosunek wartości średniej prądu do wartości średniej bezwzględnej, zawiera informacje umożliwiające lokalizację uszkodzonych...
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Programmable Digital Circuits
e-Learning Courses -
Experimental test results of an automatic voltage regulator with independent phase voltage controllers
PublicationThe growing number of distributed renewable energy sources and dynamic constant-power loads (e.g. electric vehicle charging stations) pose new challenges for network operators. These changes result in alterations to network load profiles and load flows, leading to greater voltage volatility. One effective solution to these problems can be the use of automatic voltage regulators (AVRs), which stabilize and symmetrize voltage output,...
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A Development of a Capacitive Voltage Divider for High Voltage Measurement as Part of a Combined Current and Voltage Sensor
PublicationThis article deals with the development of capacitive voltage divider for high voltage measurements and presents a method of analysis and optimization of its parameters. This divider is a part of a combined voltage and current sensor for measurements in high voltage power networks. The sensor allows continuous monitoring of the network distribution status and performs a quick diagnosis and location of possible network failures....
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Voltage Transients Transfer over Medium Voltage Instrument Transformers
PublicationThis paper presents voltage harmonic transfer accuracy problems through voltage transformers which are used in power quality monitoring systems in medium and high voltage grids. A simplified lumped parameters circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number voltage transformers typically used in medium voltage grid has been tested in the conducted disturbances...
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Voltage Harmonics Transfer through Medium Voltage Instrument Transformers
PublicationVoltage transformers are widely used in power quality monitoring systems in medium and high voltage grids. This paper presents accuracy problems related to voltage harmonics transfer through instrument transformers. A simplified lumped-parameters wideband circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number of voltage transformers have been tested in the frequency...
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Voltage profiles improvement in a power network with PV energy sources – results of a voltage regulator implementation
PublicationThe constant increase in the number of photovoltaic (PV) energy sources in distribution networks is the cause of serious voltage problems. The networks built at least a dozen years ago are not provided for the installation of a large number of micro-sources. It happens that the previously properly functioning power networks are not able to provide to consumers power with the required parameters, after installing many PV sources....
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Problems with microprocessor voltage-to-frequency and frequency-to-voltage converters implementation
PublicationThe article presents the problems of digital voltage-to-frequency and frequency-to-voltage processing. Transducer systems implemented in microprocessor technology are presented, the timing of signals and functioning algorithms are discussed. An analysis of processing errors has been performed and the results of experimental studies of realized systems are presented.
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PROJEKT ZESPOŁOWY [DK][2023/24]
e-Learning CoursesCCCLECTURE and Classes: Power supply systems for industrial facilities. Devices and main circuits of MV power stations. Short-circuit calculation. Power protection automation. Security classification according to American ANSI standards used in the EU. Microprocessor protection relays. Drive systems for medium power and medium voltage pumps. Roving inverters. PROJECT: Design of a MV switching station for a medium-power pumping...
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PROJEKT ZESPOŁOWY [ET][DK][2024/25]
e-Learning CoursesCCCLECTURE and Classes: Power supply systems for industrial facilities. Devices and main circuits of MV power stations. Short-circuit calculation. Power protection automation. Security classification according to American ANSI standards used in the EU. Microprocessor protection relays. Drive systems for medium power and medium voltage pumps. Roving inverters. PROJECT: Design of a MV switching station for a medium-power pumping...
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Fault detection in electronic circuits using test buses
PublicationA survey of test buses designed for diagnostics of digital and analog electronic circuits is presented: the IEEE 1149.1 bus for digital circuits, the IEEE 1149.4 bus for mixed-signal and the IEEE 1149.6 bus for AC coupled complex digital circuits. Each bus is presented with its structure, solution of key elements, particularly boundary registers and a set of test instructions. Diagnosis with the use of the described buses is...
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Electric shock hazard in circuits with variable-speed drives
PublicationThe conventional approach to electrical safety under fault condition in typical power systems considers earth fault currents of sinusoidal waveform and frequency of 50/60 Hz. However, in circuits with variable-speed drives, there is earth fault current flow with harmonics, and these harmonics influence the threshold of ventricular fibrillation. The paper presents earth fault current waveforms in circuits with variable-speed drives...
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Numerical Test for Stability Evaluation of Analog Circuits
PublicationIn this contribution, a new numerical test for the stability evaluation of analog circuits is presented. Usually, if an analog circuit is unstable then the roots of its characteristic equation are localized on the right half-plane of the Laplace s- plane. Because this region is unbounded, we employ the bilinear transformation to map it into the unit disc on the complex plane. Hence, the existence of any root inside the unit disc...
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Quasi-resonant DC-link voltage inverter with enhanced zero-voltage switching control
PublicationA new topology modification of the parallel quasi-resonant circuit for a dc-link voltage inverter enables regulation of the zero voltage dc-link subperiods and the dc-link voltage gradient settings. The proposed circuit is based on four MOSFET switches with free-wheeling diodes for controlled quasi-resonant recharging between L-C tank in order to assure inverter zero voltage switching (ZVS) conditions. Design optimization of the...
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Voltage Dependence of Supercapacitor Capacitance
PublicationElectronic Double-Layer Capacitors (EDLC), called Supercapacitors (SC), are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We...
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The Impact of Micro-Sources on Voltage Distortions in a Power Grid
PublicationThe increase in the number of photovoltaic (PV) systems integrated with low voltage (LV) grids has led to a great need to analyse the impact of these systems on the quality of electricity and the reliability of its supply. This paper presents and compares the energy quality requirements imposed by various countries on photovoltaic plants. Then, based on real object tests and simulation in DIgSILENT PowerFactory, the impact has...
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Programmable Digital Circuits (2023/2024)
e-Learning Courses -
Starter for Voltage Boost Converter to Harvest Thermoelectric Energy for Body-Worn Sensors
PublicationThis paper examines the suitability of selected configurations of ultra-low voltage (ULV) oscilla-tors as starters for a voltage boost converter to harvest energy from a thermoelectric generator (TEG). Important properties of particularly promising configurations, suitable for on-chip imple-mentation are compared. On this basis, an improved oscillator with a low startup voltage and a high output voltage swing is proposed. The applicability...
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Imaging of ferroelectric properties of sinter by means of Piezoresponse Force Microscopy
Open Research DataFerroelectricity is a property of certain materials [1], characterized by a spontaneous electrical polarization that can be reversed by applying an external electric field. Ferroelectric properties can be used to make capacitors with adjustable capacity. The permeability of ferroelectrics is not only regulated, but usually also very high, especially...
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Marek Pszczoła dr hab. inż.
PeopleI am a Faculty member (Department of Highway and Transportation Engineering) at the Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Poland). My main research interests include: low-temperature properties of asphalt mixtures, low temperature cracking assessment of pavement structures, road materials properties, thermal stress analysis, design of pavement structures, airfield design and analysis....
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Hybrid Modulation for Modular Voltage Source Inverters with Coupled Reactors
PublicationThis paper proposes and discusses a concept of a hybrid modulation for the control of modular voltage source inverters with coupled reactors. The use of coupled reactors as the integrating elements leads to significant reduction in the size and weight of the circuit. The proposed modulation combines novel coarsely quantized pulse amplitude modulation (CQ-PAM) and innovative space-vector pulse width modulation (SVPWM). The former...
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Synchronized six-step voltage generation in high-speed PMSM drive
PublicationSynchronized voltage generation has already been considered in the context of pulse width modulation (PWM). References prove that synchronized PWM substantially decreases subharmonics in inverter output voltage when operating with low switching-to-fundamental frequency ratio. This paper identifies problems of unsynchronized voltage generation in electric drives under six-step inverter operation. Guidelines for the synchronization...
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Modular multipulse voltage source inverters with integrating coupled reactors
PublicationA novel approach to the voltage source inverters (VSI) construction is presented in the paper. The invented inverter structures allow to operate several DC/AC converters in parallel resulting in lower voltage distortions at extremely low switching frequency. The research presented in the paper describes such a parallel operation of the VSI’s which is possible thanks to the use of coupled inductors. The eighteen-pulse and twenty-four-pulse...
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A new approach to a fast and accurate design of microwave circuits with complex topologies
PublicationA robust simulation-driven design methodology of microwave circuits with complex topologies has been presented. The general method elaborated is suitable for a wide class of N-port unconventional microwave circuits constructed as a deviation from classic design solutions. The key idea of the approach proposed lies in an iterative redesign of a conventional circuit by a sequential modification and optimisation of its atomic building...
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Quality assessment of high voltage varistors by third harmonic index
PublicationHigh voltage varistors that consist of grained ZnO have to be tested before assembling into a surge arrester. The existing methods demand a usage of high voltages and intensive currents that is inconvenient, destructive and needs extensive power consumption. Additionally, these methods require metallization of the prepared varistor structures that increases costs. We propose another method of varistors quality assessments by a...
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Medium voltage drives - challenges and requirements
PublicationThe design and application of medium voltage (MV) drives are associated with different requirements related to the line side and motor side of the drive. This paper presents a brief review of the existing challenges and requirements for employing medium voltage drives in various industries. Line side, motor side, and converterproblems and requirements are described. The aim of the paper is to review the existing problems to allow...
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Third harmonic index as a diagnostic tool of high-voltage varistors
PublicationThe recommended methods for standard testing of high-voltage varistors demand application of high voltages and intensive currents that is inconvenient and needs extensive power consumption. These methods require metallization of the prepared ZnO structures that increases costs of testing. Another method of varistor quality and endurance evaluation by the third harmonic index measurement at relatively low voltage range has been...
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Immunity of residual current devices to the impulse leakage current in circuits with variable speed drives
PublicationThis paper concerns reliability of supply in variable speed drive circuits with residual current devices. During normal operation of these circuits high value of leakage current causes unwanted tripping of residual current devices. Immunity of residual current devices to the impulse leakage current should be evaluated. The system for testing of residual current devices and results of the test are presented
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The effect of the motor filters on earth fault current waveform in circuits with variable speed drives
PublicationIn circuits with variable speed drives distorted earth fault current flows. Earth fault current distortion influences the threshold of ventricular fibrillation. This paper presents earth fault current distortion in circuits with variable speed drives when motor filter is used. Two types of motor filter are analyzed. For every type of filter the effect of earth fault current distortion on ventricular fibrillation is evaluated.
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The effect of the motor filters on earth fault current waveform in circuits with variable speed drives
PublicationIn circuits with variable speed drives distorted earth fault current flows. Earth fault current distortion influences the threshold of ventricular fibrillation. This paper presents earth fault current distortion in circuits with variable speed drives when motor filter is used. Two types of motor filter are analyzed. For every type of filter the effect of earth fault current distortion on ventricular fibrillation is evaluated.
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Static Shunt PE Voltage-Quality Controllers
PublicationThis chapter focuses on power electronics (PE)-based solutions used in distribution networks for reduction of supply-voltage-quality deterioration, from long interruptions to the harmonics. Various PE devices and their combinations are addressed for particular or a range of voltage disturbances. A particular solution is applied taking into account demands for voltage quality and network configuration. In general, there are three...
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Supercapacitors - charge redistribution and restoring voltage
PublicationThe charge in supercapacitor is stored on electrodes and in electrolyte. The charges on electrodes create the Helmholtz double layer which is formed immediately with time constant of the order of seconds, while the charge storage in electrolyte is going on with time constant of the order of hundreds seconds. When the charged supercapacitor is shorted for few seconds, the charge from electrodes is discharged while the charge in...
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Estimation of the uncertainty of the AC/AC transducer output voltage
PublicationThe paper presents a methodology for estimating uncertainty of voltage transducers processing function, on the example of CYVS411D07 voltage transducers. The analysis was conducted using the method based on the GUM Guide propagation of uncertainty law and the determination of the coverage factor based on the effective number of degrees of freedom (t-Student distribution). The paper also presents example evaluation results of measured...
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Control strategies and comparison of the Dynamic Voltage Restorer
PublicationThis paper focuses on a selection problems of mitigation of the voltage disturbance by of the Dynamic Voltage Restorers (DVR’s). In short form presented and discussed are the basis of different control strategies of the DVR. The main emphasis is placed on application of modern power electronic devices. Authors of this paper in particular occupy oneself with analysis of the power rating of the typically DVR topologies. These problems...
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AC Motor Voltage and Audible Noise Dataset
PublicationThe dataset titled AC motor voltage and audible noise waveforms in ship’s electrical drive systems with frequency converters contains the voltage and sound measurement results recorded in a marine frequency controlled AC drive system. The dataset is part of research focussing on the impact of the ship’s electrical drive systems with frequency converters on vibrations and the level of audible noise on ships. The dataset allows the...
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Static Series and Shunt-series PE Voltage-quality Controllers
PublicationAs presented in the Chap. 7 static shunt power electronics (PE) voltage-quality controllers protect the utility electrical system from the unfavorable impact of customer loads. Shunt controllers, as shown in Chap. 6, are recommended mainly for mitigation of the causes of disturbances, and not their effects in distanced nodes of a power-electronics system. In the case when reduction of disturbances effects is required, which leads...
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Rapid multi-objective simulation-driven design of compact microwave circuits
PublicationA methodology for rapid multi-objective design of compact microwave circuits is proposed. Our approach exploits point-by-point Pareto set identification using surrogate-based optimization techniques, auxiliary equivalent circuit models, and space mapping as the major model correction method. The proposed technique is illustrated and validated through the design of a compact rat-race coupler. A set of ten designs being trade-offs...
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Voltage control in a power system with renewable sources of energy
PublicationIntensive development of distributed generation in power systems, caused by the European Union energy policy, gives possibility for improving safety in power delivery as well as optimizing the costs of the systems functioning. In this context, distributed generation can be used for voltage control in power systems – it can be performed by the control of reactive power of each source of energy or a group of energy sources. This...
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Fractional-order Systems and Synchronous Generator Voltage Regulator
PublicationModern regulators of synchronous generators, including voltage regulators, are digital systems, in their vast majority with standard structures contained in the IEEE standard. These are systems described with stationary differential equations of integral order. Differential equations of fractional order are not employed in regulators for synchronous generator control. This paper presents an analysis of the possibilities of using...
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Medium-Voltage Drives: Challenges and existing technology
PublicationThe article presents an overview of state-of-art solutions, advances, and design and research trends in medium-voltage (MV) drive technologies - and also discusses the challenges and requirements associated with the use of such drives. The choice and deployment of MV drives in industries are associated with numerous requirements related to the front-end converter (grid side) and inverter (machine side). The focus is on solutions...
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A new approach to cross-bonding in medium voltage cable lines
PublicationThe medium voltage underground cable sheaths are usually bonded and earthed in every substation on the cable route. This results in additional power losses in the sheaths. The paper presents an idea of reducing power losses caused by sheaths cross-bonding. The idea of sheaths cross-connecting only in selected MV/LV substations is given instead of a typical solution, where sheaths cross-bonding requires installing additional joints...
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DC-link voltage balancing in cascaded H-Bridge converters
PublicationIn the paper a DC-link voltage balancing strategy for multilevel Cascaded H-Bridge (CHB) converter is proposed. Presented solution bases on optimal choice of active vector durations in Space-Vector Pulse Width Modulation (SV-PWM). It makes it possible to DC-link voltages control and to properly generate the output voltage vector in the case of DC-link voltage unbalance. Results of simulation and experimental researches...
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Atomistic Surrogate-Based Optimization for Simulation-Driven Design of Computationally Expensive Microwave Circuits with Compact Footprints
PublicationA robust simulation-driven design methodology for computationally expensive microwave circuits with compact footprints has been presented. The general method introduced in this chapter is suitable for a wide class of N-port un-conventional microwave circuits constructed as a deviation from classic design solutions. Conventional electromagnetic (EM) simulation-driven design routines are generally prohibitive when applied to numerically...
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Voltage and Current Unbalance Reduction in Power Networks with Distributed Generation and Electric Vehicles
PublicationThe current development of prosumer microsources and the expected spread of electric vehicles may cause the appearance of significant current and voltage unbalance in low-voltage (LV) networks. This unbalance, which is an unfavorable phenomenon, may occur when using single-phase photovoltaic (PV) microsources and single-phase home chargers for electric vehicles. This paper presents a proposal for the symmetrization of the LV network...
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Classification of high-voltage varistors into groups of differentiated quality
PublicationThe research was aimed on defining a factor of quality for high-voltage varistors using Non-Destructive Testing (NDT) techniques, which could be applied during the production testing. The newly proposed parameter Q determined on the basis of the lowest resonant frequency fr measured within the preselected frequency range was taken into account. The parameter Q was defined for ZnO structures after firing, without metallized contacts....