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The aim of the study is to develop a suitable method for thermographic control of corrosion in parts of magnesium alloys used in electronic packaging. Specimens with different thickness, representative of magnesium alloys of the three typical groups are studied: AZ91, AM50 and AE42. Thermographic investigation is conducted for the both specimens: without corrosion and corroded specimens in an environment...
Using SMD packages with high power dissipation is challenging. To cool the SMD power packages, the state of the art solution is to use a PCB with thermal vias to extract the heat from the electronic package [1]. This solution has the disadvantage that the thermal resistance from package to heatsink is relatively high, in the range of 5–10 K/W. A new solution for cooling is proposed, in which the heatsink...
This paper analyses the influence of temperature of the CPU of an embedded device, mainly on the application execution time. The study is performed on an AtMega8L microcontroller, placed in a thermal chamber, where different temperatures were set, to show how increasing the temperature can affect the microcontroller speed. Also, several speed configurations were built, using oscillators of 1MHz and...
The article examines the use of compact models and the thermal design of LED applications. The study shows that despite the simplified representation of the thermal behavior, compact models predict the transition temperature with a sufficiently good accuracy in the initial project phase. An evaluation of methods for further improvement in predictive accuracy is made.
With decreasing solder volumes and joint sizes, new aspects in electronics packaging occur. Previous publications report porous structures in Cu/Sn microbump interconnects after flux-assisted bonding and storage. The origin and mechanisms of pore formation are still discussed among researchers. In this study, the influence of no-clean flux during isothermal storage is investigated on soldered Cu/SnAg3...
The thermal, laboratory model of multi-core microprocessor was fabricated and analyzed. It consists of four separately powered thick-film resistors. Moreover, thermoelectric temperature sensor, suitable for monitoring of small and dynamic temperature changes on the microprocessor/heat sink border, was designed and tested. It consists of two separate substrates connected by nickel and silver wires...
This paper deals with comparison of copper (Thick Printed Copper) and silver thick films on alumina substrates properties. Thick film technology is used in many fields of electronic industry. Thick printed copper is a new prospective technology, which is used for power electronics substrate manufacturing. Comparison of adhesion, solderability and other properties of TPC technology and silver thick...
In this study, novel flexible organic light-emitting diode structure (f-OLED) hybrimer/polymer/metal/polymer/emissive layer/metal was proposed. We studied the effect of the mechanical bending on its electro-optical behavior. The device contains polymeric based anode PEDOT:PSS/Au/PEDOT:PSS, where the conductive polymer was spray deposited on preliminary UV exposed hybrimer surface. It was found enhancement...
The modern locomotives, which are in exploitation in the railway network in Bulgaria, are equipped with electronic devices for registration of analogue and digital running parameters (i.e. the so-called “black boxes” or “recording devices”). Such systems are the Hasler TEL 1000 and the DSK type from KWR. The registration devices used in the older locomotives are not digital, but mechanical. Since...
The aim of our study is to synthesize nano-sized magnetite in the porous texture of activated carbon (with different concentration). Our main hypothesis is that the porous texture of activated carbon contains a significant amount of nano-sized pores. By steric reasons if magnetite synthesized in situ in the porous texture of activated carbon, it will be nanosized too. The fillers have been characterized...
Technical requirements for materials in manufacturing of electronics are complex and in constant change. Especially demands have been raised in the area of environmental issues. Polymers based on renewable resources provide some interesting approaches to meet these demands. A general overview of polymers based on renewable resources is given highlighting the fascinating properties of these polymers...
In this paper the proposed configuration of a digitally controllable non-inverting RC integrator, employing 4-terminal CFOA is an object of analysis and simulation modeling. Based on a theoretical analysis of the circuit the equations for the transfer functions and formulas for the related electrical parameters are obtained. By using the synthesized circuit of an integrator a programmable CFOA-based...
This paper presents a methodology for parameters extraction of photovoltaic cell based on real measurement. The modeling of equivalent schemes of solar cells is of great importance in order to be included in electric circuits for wireless sensor networks power supply. The parameters extraction of these devices is still a very difficult task, which requires experimental data, computing and modeling...
The vapour concentration reduction process in a vacuum type Vapour Phase Soldering (VPS) oven was investigated by numerical simulations. The low vapour pressure is applied to decrease the number of voids during the formation of solder joints. This paper contains the preliminary preparations of a detailed numerical modeling of the vacuum VPS oven and the scientific examination of the problem. A three-dimensional...
This article presents a research focused on printed circuit board (PCB) protective coatings as an option for cover the assembled PCBs and electronic device reliability improvement. The experiment with five different coatings is described in the article. For the experiment rigid substrate (FR-4) and flexible substrate (Kapton) were used. The protective coatings from acrylic, urethane, silicone and...
The aim of this article is to explore the reliability of electronic units, which are parts of complex electronic systems. A failure rates estimation of such units is performed, following a technique based on data for their technical characteristics, such as circuit diagrams, operational regimes and component specifications. A comparison is made of the values obtained with analogous data, valid for...
Mechanical stress act on solder joints during transport, function and storage of the electronic equipment. Therefore, the knowledge of solder joints resistance against it is very useful. This article deals with comparison of mechanical resistance of SnCu0,7 and Sn42Bi58 solder alloys. The experiments were based on two PCBs (smaller and larger one, with soldering pads designed according to commonly...
This paper deals with the design of passive components created on flexible substrates by the screen printing technology and the aging influence on their electrical parameters. The screen printing technology is current used for printed passive components such as resistors, inductors, capacitors. Now there are many types of patterns for these passive components and many screen printing pastes on the...
Noise and nonlinearity of the voltage vs. current characteristic of conductive adhesive joints were examined in dependence on the value of the joint resistance. Changes in the resistance were caused by different types of climatic ageing. Two types of adhesives, AX12EV and ELPOX SC515 (both Amepox, Poland) based on bis-phenol epoxy matrix and silver filler were used for formation of the adhesive bonds...
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