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Power-off Testing
Power-off testing is often necessary to test the printed circuit assembly (PCA) board due to uncertainty as to the nature of the failure. When the PCA can be further damaged by applying power it is necessary to use power off test techniques to safely examine it. Power off testing includes analog signature analysis, ohmmeter, LCR Meter and optical inspection. This type of testing also lends itself well to troubleshooting circuit boards without the aid of supporting documentation such as schematics. Typical equipment * Analog signature analysis* * Huntron Tracker* * Automated optical inspection * LCR meter * Machine vision * Ohmmeter An analog ohmmeter An ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multimeters also function as ohmmeters when in resistance-measu ... Printed circuit board manufacturing Nondestructive testing Hardware testing Electricity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Assembly
A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with an artwork pattern of traces, planes and other features (similar to wires on a flat surface) etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds vias: plated-through holes that allow interconnections between layers. Printed circuit boards are used in nearly all electronic products. Alternatives to PCBs include wire wrap a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Signature Analysis
{{unreferenced, date=February 2015 Analog signature analysis is electronic component and circuit board troubleshooting technique which applies a current-limited AC sinewave across two points of an electronic component or circuit. The resulting current/voltage waveform is shown on a signature display using vertical deflection for current and horizontal deflection for voltage. This unique analog signature represents the overall health of the part being analyzed. By comparing the signatures of known good circuit boards to those of suspect boards, faulty nets and components can be quickly identified. Analog Signature Analysis relies on a change in electrical characteristics to detect problems on a circuit board. Other terms * ATE diagnostics * Power off nodal impedance test * Power-off testing * Tracker signature analysis * VI testing * VI curves * Voltage-versus-current display * V/I trace test Typical equipment * Flying probe * Octopus * VI interceptor * V/I curve tracer * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohmmeter
An analog ohmmeter An ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multimeters also function as ohmmeters when in resistance-measuring mode. An ohmmeter applies current to the circuit or component whose resistance is to be measured. It then measures the resulting voltage and calculates the resistance using Ohm’s law V=IR. An ohmmeter should not be connected to a circuit or component that is carrying a current or is connected to a power source. Power should be disconnected before connecting the ohmmeter. Ohmmeters can be either connected in series or parallel based on requirements (whether resistance being measured is part of circuit or is a shunt resistance.) Micro-ohmmeters (microhmmeter or micro ohmmeter) make measurements of low resistance. Megohmmeters (also a trademarked device Megger) measure large values of resistance. The unit of measurement for resist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Signature Analysis
{{unreferenced, date=February 2015 Analog signature analysis is electronic component and circuit board troubleshooting technique which applies a current-limited AC sinewave across two points of an electronic component or circuit. The resulting current/voltage waveform is shown on a signature display using vertical deflection for current and horizontal deflection for voltage. This unique analog signature represents the overall health of the part being analyzed. By comparing the signatures of known good circuit boards to those of suspect boards, faulty nets and components can be quickly identified. Analog Signature Analysis relies on a change in electrical characteristics to detect problems on a circuit board. Other terms * ATE diagnostics * Power off nodal impedance test * Power-off testing * Tracker signature analysis * VI testing * VI curves * Voltage-versus-current display * V/I trace test Typical equipment * Flying probe * Octopus * VI interceptor * V/I curve tracer * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automated Optical Inspection
Automated optical inspection (AOI) is an automated visual inspection Visual inspection is a common method of quality control, data acquisition, and data analysis. Visual Inspection, used in maintenance of facilities, mean inspection of equipment and structures using either or all of raw human senses such as vision, ... of printed circuit board (PCB) (or LCD, transistor) manufacture where a camera machine vision, autonomously scans the device under test for both catastrophic failure (e.g. missing component) and Product defect, quality defects (e.g. fillet size or shape or component skew). It is commonly used in the manufacturing process because it is a non-contact test method. It is implemented at many stages through the manufacturing process including bare board inspection, solder paste inspection (SPI), pre-reflow and post-reflow as well as other stages. Historically, the primary place for AOI systems has been after solder reflow or "post-production." Mainly because, post-reflow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LCR Meter
An LCR meter is a type of electronic test equipment used to measure the inductance (L), capacitance (C), and resistance (R) of an electronic component. In the simpler versions of this instrument the impedance was measured internally and converted for display to the corresponding capacitance or inductance value. Readings should be reasonably accurate if the capacitor or inductor device under test does not have a significant resistive component of impedance. More advanced designs measure true inductance or capacitance, as well as the equivalent series resistance of capacitors and the Q factor of inductive components. Operation Usually the device under test (DUT) is subjected to an AC voltage source. The meter measures the voltage across and the current through the DUT. From the ratio of these the meter can determine the magnitude of the impedance. The phase angle between the voltage and current is also measured in more advanced instruments; in combination with the impedance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine Vision
Machine vision (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry. Machine vision refers to many technologies, software and hardware products, integrated systems, actions, methods and expertise. Machine vision as a systems engineering discipline can be considered distinct from computer vision, a form of computer science. It attempts to integrate existing technologies in new ways and apply them to solve real world problems. The term is the prevalent one for these functions in industrial automation environments but is also used for these functions in other environment vehicle guidance. The overall machine vision process includes planning the details of the requirements and project, and then creating a solution. During run-time, the process starts with imaging, followed by automated analysis of the image and extraction of the requir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohmmeter
An analog ohmmeter An ohmmeter is an electrical instrument that measures electrical resistance (the opposition offered by a circuit or component to the flow of electric current). Multimeters also function as ohmmeters when in resistance-measuring mode. An ohmmeter applies current to the circuit or component whose resistance is to be measured. It then measures the resulting voltage and calculates the resistance using Ohm’s law V=IR. An ohmmeter should not be connected to a circuit or component that is carrying a current or is connected to a power source. Power should be disconnected before connecting the ohmmeter. Ohmmeters can be either connected in series or parallel based on requirements (whether resistance being measured is part of circuit or is a shunt resistance.) Micro-ohmmeters (microhmmeter or micro ohmmeter) make measurements of low resistance. Megohmmeters (also a trademarked device Megger) measure large values of resistance. The unit of measurement for resist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printed Circuit Board Manufacturing
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The earliest known form of printing as applied to paper was woodblock printing, which appeared in China before 220 AD for cloth printing. However, it would not be applied to paper until the seventh century.Shelagh Vainker in Anne Farrer (ed), "Caves of the Thousand Buddhas", 1990, British Museum publications, Later developments in printing technology include the movable type invented by Bi Sheng around 1040 AD and the printing press invented by Johannes Gutenberg in the 15th century. The technology of printing played a key role in the development of the Renaissance and the Scientific Revolution and laid the material basis for the modern knowledge-based economy and the spread of learning to the masses. History Woodblock printing Woodblock pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nondestructive Testing
Nondestructive testing (NDT) is any of a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive examination (NDE), nondestructive inspection (NDI), and nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research. The six most frequently used NDT methods are eddy-current, magnetic-particle, liquid penetrant, radiographic, ultrasonic, and visual testing. NDT is commonly used in forensic engineering, mechanical engineering, petroleum engineering, electrical engineering, civil engineering, systems engineering, aeronautical engineering, medicine, and art. Innovations in the field of nondestructive testing have had a profound impact on medical im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardware Testing
Hardware may refer to: Technology Computing and electronics * Electronic hardware, interconnected electronic components which perform analog or logic operations ** Digital electronics, electronics that operate on digital signals *** Computer hardware, physical parts of a computer *** Networking hardware, devices that enable use of a computer network ** Electronic component, device in an electronic system used to affect electrons, usually industrial products Other technologies * Household hardware, equipment used for home repair and other work, such as fasteners, wire, plumbing supplies, electrical supplies, utensils, and machine parts *Builders hardware, metal hardware for building fixtures, such as hinges and latches * Hardware (development cooperation), in technology transfer * Drum hardware, used to tension, position, and support the instruments * Military technology, application of technology to warfare * Music hardware, devices other than instruments to create music Entertain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
