id stringlengths 24 24 | question stringlengths 1 270 | answer stringlengths 1 239 | documents listlengths 1 1 |
|---|---|---|---|
572fa37304bcaa1900d76b28 | What does the "NCD" in "NCD files" mean? | numerically controlled drill | [
"Printed_circuit_board\n\nHoles through a PCB are typically drilled with small-diameter drill bits made of solid coated tungsten carbide. Coated tungsten carbide is recommended since many board materials are very abrasive and drilling must be high RPM and high feed to be cost effective. Drill bits must also remain ... |
572fa37304bcaa1900d76b29 | What's another name for NCD files that has an "x" in it? | Excellon files | [
"Printed_circuit_board\n\nHoles through a PCB are typically drilled with small-diameter drill bits made of solid coated tungsten carbide. Coated tungsten carbide is recommended since many board materials are very abrasive and drilling must be high RPM and high feed to be cost effective. Drill bits must also remain ... |
572fa92fb2c2fd14005682d3 | What do the hole walls in two-layer PCBs have to be before they can be electroplated? | conductive | [
"Printed_circuit_board\n\nThe hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes. These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces... |
572fa92fb2c2fd14005682d4 | What's the minimum number of layers a PCB can have to be considered "multi-layer"? | three | [
"Printed_circuit_board\n\nThe hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes. These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces... |
572fa92fb2c2fd14005682d5 | What process does a multi-layer PCB usually undergo before plating to make sure the layers have good connectivity with each other? | de-smear | [
"Printed_circuit_board\n\nThe hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes. These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces... |
572fa92fb2c2fd14005682d6 | What type of boards undergo the etch-back process? | high reliability | [
"Printed_circuit_board\n\nThe hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes. These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces... |
572fa92fb2c2fd14005682d7 | Etch-back removes glass fibers and what other material? | resin | [
"Printed_circuit_board\n\nThe hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes. These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces... |
572fb2d4b2c2fd140056836d | What happens to untreated copper that makes it difficult to solder? | oxidizes | [
"Printed_circuit_board\n\nMatte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickl... |
572fb2d4b2c2fd140056836e | What chemical treatment will prevent bare copper from oxidizing? | benzimidazolethiol | [
"Printed_circuit_board\n\nMatte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickl... |
572fb2d4b2c2fd140056836f | What's the process by which bare copper gets covered in solder? | hot air solder levelling | [
"Printed_circuit_board\n\nMatte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickl... |
572fb2d4b2c2fd1400568370 | What does hot air solder leveling ensure the coated copper will have? | solderable surface | [
"Printed_circuit_board\n\nMatte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickl... |
572fb2d4b2c2fd1400568371 | What alloy can no longer be used in HASL because of restrictions on the use of one of its metal components? | tin-lead | [
"Printed_circuit_board\n\nMatte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickl... |
572fb4cfb2c2fd1400568381 | What does OSP stand for? | organic surface protectant | [
"Printed_circuit_board\n\nOther platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG) and direct gold plating (over nickel). Edge connectors, placed along one ... |
572fb4cfb2c2fd1400568382 | What metal is often under the gold plating on edge connectors? | nickel | [
"Printed_circuit_board\n\nOther platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG) and direct gold plating (over nickel). Edge connectors, placed along one ... |
572fb4cfb2c2fd1400568383 | What's the abbreviation for immersion silver plating? | IAg | [
"Printed_circuit_board\n\nOther platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG) and direct gold plating (over nickel). Edge connectors, placed along one ... |
572fb4cfb2c2fd1400568384 | Ag3Cu is one intermetallic that tin forms; what's the other one? | Cu5Sn6 | [
"Printed_circuit_board\n\nOther platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG) and direct gold plating (over nickel). Edge connectors, placed along one ... |
572fb4cfb2c2fd1400568385 | What might the rapid diffusion of coating metal into tin solder leave in the surface coating? | voids | [
"Printed_circuit_board\n\nOther platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG) and direct gold plating (over nickel). Edge connectors, placed along one ... |
572fb648b2c2fd140056839d | What's the process whereby metal filaments are grown on or in a PCB via DC voltage? | Electrochemical migration | [
"Printed_circuit_board\n\nElectrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. Silver, zinc, and aluminum are known to grow whiskers under the influence of an electric field. Silver also grows conducting surface ... |
572fb648b2c2fd140056839e | Along with silver and aluminum, what metal grows metal filaments when exposed to an electric field? | zinc | [
"Printed_circuit_board\n\nElectrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. Silver, zinc, and aluminum are known to grow whiskers under the influence of an electric field. Silver also grows conducting surface ... |
572fb648b2c2fd140056839f | In addition to "whiskers," what does silver sprout around ions like halide? | conducting surface paths | [
"Printed_circuit_board\n\nElectrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. Silver, zinc, and aluminum are known to grow whiskers under the influence of an electric field. Silver also grows conducting surface ... |
572fb648b2c2fd14005683a0 | What do scientist call the function whereby tin changes when it's very cold? | tin pest | [
"Printed_circuit_board\n\nElectrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. Silver, zinc, and aluminum are known to grow whiskers under the influence of an electric field. Silver also grows conducting surface ... |
572fb648b2c2fd14005683a1 | What's present in plated surfaces that causes tin to grow metal filaments? | tension | [
"Printed_circuit_board\n\nElectrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. Silver, zinc, and aluminum are known to grow whiskers under the influence of an electric field. Silver also grows conducting surface ... |
572fd395b2c2fd14005684bd | If part of a PCB isn't solderable, what can be used instead? | solder resist | [
"Printed_circuit_board\n\nAreas that should not be soldered may be covered with solder resist (solder mask). One of the most common solder resists used today is called \"LPI\" (liquid photoimageable solder mask). A photo-sensitive coating is applied to the surface of the PWB, then exposed to light through the sold... |
572fd395b2c2fd14005684be | What's another term used for "solder resist"? | solder mask | [
"Printed_circuit_board\n\nAreas that should not be soldered may be covered with solder resist (solder mask). One of the most common solder resists used today is called \"LPI\" (liquid photoimageable solder mask). A photo-sensitive coating is applied to the surface of the PWB, then exposed to light through the sold... |
572fd395b2c2fd14005684bf | What solder resist with a four-word name is a popular choice in the industry? | liquid photoimageable solder mask | [
"Printed_circuit_board\n\nAreas that should not be soldered may be covered with solder resist (solder mask). One of the most common solder resists used today is called \"LPI\" (liquid photoimageable solder mask). A photo-sensitive coating is applied to the surface of the PWB, then exposed to light through the sold... |
572fd395b2c2fd14005684c0 | What kind of coating gets applied to the PWB before light exposure? | photo-sensitive | [
"Printed_circuit_board\n\nAreas that should not be soldered may be covered with solder resist (solder mask). One of the most common solder resists used today is called \"LPI\" (liquid photoimageable solder mask). A photo-sensitive coating is applied to the surface of the PWB, then exposed to light through the sold... |
572fd395b2c2fd14005684c1 | What solder resist is so inaccurate that few choose it anymore? | screen print epoxy ink | [
"Printed_circuit_board\n\nAreas that should not be soldered may be covered with solder resist (solder mask). One of the most common solder resists used today is called \"LPI\" (liquid photoimageable solder mask). A photo-sensitive coating is applied to the surface of the PWB, then exposed to light through the sold... |
572fd62fb2c2fd14005684e9 | What are bare-board tests looking for besides "opens"? | "shorts" | [
"Printed_circuit_board\n\nUnpopulated boards are usually bare-board tested for \"shorts\" and \"opens\". A short is a connection between two points that should not be connected. An open is a missing connection between points that should be connected. For high-volume production a fixture or a rigid needle adapter is... |
572fd62fb2c2fd14005684ea | What's an absent connection that needs to be linked up on an unpopulated board called? | An open | [
"Printed_circuit_board\n\nUnpopulated boards are usually bare-board tested for \"shorts\" and \"opens\". A short is a connection between two points that should not be connected. An open is a missing connection between points that should be connected. For high-volume production a fixture or a rigid needle adapter is... |
572fd62fb2c2fd14005684eb | What conductive metal are the lands on a circuit board made out of? | copper | [
"Printed_circuit_board\n\nUnpopulated boards are usually bare-board tested for \"shorts\" and \"opens\". A short is a connection between two points that should not be connected. An open is a missing connection between points that should be connected. For high-volume production a fixture or a rigid needle adapter is... |
572fd62fb2c2fd14005684ec | What does a flying probe tester deliver to the contact points during testing? | voltage | [
"Printed_circuit_board\n\nUnpopulated boards are usually bare-board tested for \"shorts\" and \"opens\". A short is a connection between two points that should not be connected. An open is a missing connection between points that should be connected. For high-volume production a fixture or a rigid needle adapter is... |
572fd62fb2c2fd14005684ed | What system tells the flying probe where to go and what to do? | CAM system | [
"Printed_circuit_board\n\nUnpopulated boards are usually bare-board tested for \"shorts\" and \"opens\". A short is a connection between two points that should not be connected. An open is a missing connection between points that should be connected. For high-volume production a fixture or a rigid needle adapter is... |
572fdf4104bcaa1900d76e27 | Surface-mount is one type of construction used in PCB assembly; what's the other one? | through-hole | [
"Printed_circuit_board\n\nOften, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting... |
572fdf4104bcaa1900d76e28 | Which type of construction makes components that use more space? | through-hole | [
"Printed_circuit_board\n\nOften, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting... |
572fdf4104bcaa1900d76e29 | Which of the two kinds of construction is weaker under strain? | surface-mount | [
"Printed_circuit_board\n\nOften, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting... |
572fdf4104bcaa1900d76e2a | If you're building a circuit board that has a lot of components that won't be used, which construction would be better? | surface-mount | [
"Printed_circuit_board\n\nOften, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting... |
572fe0d1947a6a140053cd9c | Do test circuits create permanent or temporary connections between traces? | temporary | [
"Printed_circuit_board\n\nIn boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most ... |
572fe0d1947a6a140053cd9d | What's the most frequently used test configuration procedure for ICs? | Joint Test Action Group | [
"Printed_circuit_board\n\nIn boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most ... |
572fe0d1947a6a140053cd9e | What would you avoid by using the Joint Test Action Group standard? | physical test probes | [
"Printed_circuit_board\n\nIn boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most ... |
572fe0d1947a6a140053cd9f | What component of the printed circuit board is appraised with boundary scan testing? | ICs | [
"Printed_circuit_board\n\nIn boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most ... |
572fe0d1947a6a140053cda0 | To whom would you go to acquire the algorithms you'd use for the Joint Test Action Group procedures? | JTAG tool vendors | [
"Printed_circuit_board\n\nIn boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most ... |
572fe1edb2c2fd1400568553 | If a PCB is intended for use in an setting with extreme conditions, what would probably be applied? | conformal coating | [
"Printed_circuit_board\n\nPCBs intended for extreme environments often have a conformal coating, which is applied by dipping or spraying after the components have been soldered. The coat prevents corrosion and leakage currents or shorting due to condensation. The earliest conformal coats were wax; modern conformal ... |
572fe1edb2c2fd1400568554 | A conformal coating can be applied by spraying the PCB or by doing what else to it? | dipping | [
"Printed_circuit_board\n\nPCBs intended for extreme environments often have a conformal coating, which is applied by dipping or spraying after the components have been soldered. The coat prevents corrosion and leakage currents or shorting due to condensation. The earliest conformal coats were wax; modern conformal ... |
572fe1edb2c2fd1400568555 | The conformal coating can prevent leaking, shorts, and what other type of moisture damage? | corrosion | [
"Printed_circuit_board\n\nPCBs intended for extreme environments often have a conformal coating, which is applied by dipping or spraying after the components have been soldered. The coat prevents corrosion and leakage currents or shorting due to condensation. The earliest conformal coats were wax; modern conformal ... |
572fe1edb2c2fd1400568556 | What material was first used for conformal coating? | wax | [
"Printed_circuit_board\n\nPCBs intended for extreme environments often have a conformal coating, which is applied by dipping or spraying after the components have been soldered. The coat prevents corrosion and leakage currents or shorting due to condensation. The earliest conformal coats were wax; modern conformal ... |
572fe1edb2c2fd1400568557 | What action is made much more difficult for boards that have a conformal coating? | servicing | [
"Printed_circuit_board\n\nPCBs intended for extreme environments often have a conformal coating, which is applied by dipping or spraying after the components have been soldered. The coat prevents corrosion and leakage currents or shorting due to condensation. The earliest conformal coats were wax; modern conformal ... |
572fe399a23a5019007fcae1 | What special protection are most PCBs shipped in? | antistatic bags | [
"Printed_circuit_board\n\nMany assembled PCBs are static sensitive, and therefore must be placed in antistatic bags during transport. When handling these boards, the user must be grounded (earthed). Improper handling techniques might transmit an accumulated static charge through the board, damaging or destroying co... |
572fe399a23a5019007fcae2 | What's another term for "grounded" in the context of PCBs? | earthed | [
"Printed_circuit_board\n\nMany assembled PCBs are static sensitive, and therefore must be placed in antistatic bags during transport. When handling these boards, the user must be grounded (earthed). Improper handling techniques might transmit an accumulated static charge through the board, damaging or destroying co... |
572fe399a23a5019007fcae3 | What force can easily change or even completely destroy an etch on a PCB? | static charge | [
"Printed_circuit_board\n\nMany assembled PCBs are static sensitive, and therefore must be placed in antistatic bags during transport. When handling these boards, the user must be grounded (earthed). Improper handling techniques might transmit an accumulated static charge through the board, damaging or destroying co... |
572fe399a23a5019007fcae4 | What class of PCBs are even more susceptible to static than standard ones? | non-traditional | [
"Printed_circuit_board\n\nMany assembled PCBs are static sensitive, and therefore must be placed in antistatic bags during transport. When handling these boards, the user must be grounded (earthed). Improper handling techniques might transmit an accumulated static charge through the board, damaging or destroying co... |
572fe399a23a5019007fcae5 | Non-traditional PCBs include microwave PCBs and what other type of board? | MCMs | [
"Printed_circuit_board\n\nMany assembled PCBs are static sensitive, and therefore must be placed in antistatic bags during transport. When handling these boards, the user must be grounded (earthed). Improper handling techniques might transmit an accumulated static charge through the board, damaging or destroying co... |
572fe51904bcaa1900d76e5f | If a lead wasn't soldered manually, what device was used? | wave soldering machine | [
"Printed_circuit_board\n\nThe first PCBs used through-hole technology, mounting electronic components by leads inserted through holes on one side of the board and soldered onto copper traces on the other side. Boards may be single-sided, with an unplated component side, or more compact double-sided boards, with com... |
572fe51904bcaa1900d76e60 | Which type of PCB construction technique was used first? | through-hole | [
"Printed_circuit_board\n\nThe first PCBs used through-hole technology, mounting electronic components by leads inserted through holes on one side of the board and soldered onto copper traces on the other side. Boards may be single-sided, with an unplated component side, or more compact double-sided boards, with com... |
572fe51904bcaa1900d76e61 | In through-hole construction, what are the leads on the front attached to on the back? | copper traces | [
"Printed_circuit_board\n\nThe first PCBs used through-hole technology, mounting electronic components by leads inserted through holes on one side of the board and soldered onto copper traces on the other side. Boards may be single-sided, with an unplated component side, or more compact double-sided boards, with com... |
572fe51904bcaa1900d76e62 | For boards with two sides, to what angle are leads bent to in order to install them horizontally? | 90 degrees | [
"Printed_circuit_board\n\nThe first PCBs used through-hole technology, mounting electronic components by leads inserted through holes on one side of the board and soldered onto copper traces on the other side. Boards may be single-sided, with an unplated component side, or more compact double-sided boards, with com... |
572fe51904bcaa1900d76e63 | What is improved by bending leads in opposite directions on the back of double-sided PCBs? | mechanical strength | [
"Printed_circuit_board\n\nThe first PCBs used through-hole technology, mounting electronic components by leads inserted through holes on one side of the board and soldered onto copper traces on the other side. Boards may be single-sided, with an unplated component side, or more compact double-sided boards, with com... |
572fe9d5a23a5019007fcb2b | Which type of construction is more expensive? | Through-hole | [
"Printed_circuit_board\n\nThrough-hole manufacture adds to board cost by requiring many holes to be drilled accurately, and limits the available routing area for signal traces on layers immediately below the top layer on multi-layer boards since the holes must pass through all layers to the opposite side. Once surf... |
572fe9d5a23a5019007fcb2c | What type of boards end up with limited routing space in through-hole manufacture? | multi-layer | [
"Printed_circuit_board\n\nThrough-hole manufacture adds to board cost by requiring many holes to be drilled accurately, and limits the available routing area for signal traces on layers immediately below the top layer on multi-layer boards since the holes must pass through all layers to the opposite side. Once surf... |
572fe9d5a23a5019007fcb2d | What force might damage a PCB if large components are surface mounted? | mechanical stress | [
"Printed_circuit_board\n\nThrough-hole manufacture adds to board cost by requiring many holes to be drilled accurately, and limits the available routing area for signal traces on layers immediately below the top layer on multi-layer boards since the holes must pass through all layers to the opposite side. Once surf... |
572fe9d5a23a5019007fcb2e | What components can be surface mounted to save space? | small-sized SMD components | [
"Printed_circuit_board\n\nThrough-hole manufacture adds to board cost by requiring many holes to be drilled accurately, and limits the available routing area for signal traces on layers immediately below the top layer on multi-layer boards since the holes must pass through all layers to the opposite side. Once surf... |
572fe9d5a23a5019007fcb2f | A component might not be able to be made any smaller because of its mechanical limitations or what other need? | power requirements | [
"Printed_circuit_board\n\nThrough-hole manufacture adds to board cost by requiring many holes to be drilled accurately, and limits the available routing area for signal traces on layers immediately below the top layer on multi-layer boards since the holes must pass through all layers to the opposite side. Once surf... |
572ff7d704bcaa1900d76f5b | When did surface-mount become a commonly used manufacturing process? | mid-1990s | [
"Printed_circuit_board\n\nSurface-mount technology emerged in the 1960s, gained momentum in the early 1980s and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass throug... |
572ff7d704bcaa1900d76f5c | What did the new components with end tabs replace? | wire leads | [
"Printed_circuit_board\n\nSurface-mount technology emerged in the 1960s, gained momentum in the early 1980s and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass throug... |
572ff7d704bcaa1900d76f5d | What improvement is possible with surface-mounting that enables higher production and lower labor costs? | automation | [
"Printed_circuit_board\n\nSurface-mount technology emerged in the 1960s, gained momentum in the early 1980s and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass throug... |
572ff7d704bcaa1900d76f5e | What are SMDs? | surface mount devices | [
"Printed_circuit_board\n\nSurface-mount technology emerged in the 1960s, gained momentum in the early 1980s and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass throug... |
572ff7d704bcaa1900d76f5f | Is it the chip or the package that influences the price of an SMD more? | chip | [
"Printed_circuit_board\n\nSurface-mount technology emerged in the 1960s, gained momentum in the early 1980s and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass throug... |
572ff9bf04bcaa1900d76f95 | What process is a trace left over from? | etching | [
"Printed_circuit_board\n\nEach trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In ... |
572ff9bf04bcaa1900d76f96 | Along with thickness, what determines the resistance of a trace? | width | [
"Printed_circuit_board\n\nEach trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In ... |
572ff9bf04bcaa1900d76f97 | What type of trace is often narrower than a ground trace? | signal | [
"Printed_circuit_board\n\nEach trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In ... |
572ff9bf04bcaa1900d76f98 | In a multi-layer board, what metal would a ground plane be mostly made out of? | copper | [
"Printed_circuit_board\n\nEach trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In ... |
572ff9bf04bcaa1900d76f99 | What type of circuits use a stripline and microstrip format? | microwave circuits | [
"Printed_circuit_board\n\nEach trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In ... |
572ffb33a23a5019007fcbfb | What element of a laminate is designated by the cloth to resin ratio, among other things? | type designation | [
"Printed_circuit_board\n\nThe cloth or fiber material used, resin material, and the cloth to resin ratio determine the laminate's type designation (FR-4, CEM-1, G-10, etc.) and therefore the characteristics of the laminate produced. Important characteristics are the level to which the laminate is fire retardant, th... |
572ffb33a23a5019007fcbfc | What's the name for the measurement of a laminate's change in thickness as its temperature changes? | Z-axis expansion coefficient | [
"Printed_circuit_board\n\nThe cloth or fiber material used, resin material, and the cloth to resin ratio determine the laminate's type designation (FR-4, CEM-1, G-10, etc.) and therefore the characteristics of the laminate produced. Important characteristics are the level to which the laminate is fire retardant, th... |
572ffb33a23a5019007fcbfd | What's the abbreviation for the glass transition temperature of a laminate? | Tg | [
"Printed_circuit_board\n\nThe cloth or fiber material used, resin material, and the cloth to resin ratio determine the laminate's type designation (FR-4, CEM-1, G-10, etc.) and therefore the characteristics of the laminate produced. Important characteristics are the level to which the laminate is fire retardant, th... |
572fffeb947a6a140053cf38 | What's the common name of polytetrafluoroethylene? | Teflon | [
"Printed_circuit_board\n\nThere are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB indu... |
572fffeb947a6a140053cf39 | What pre-preg material is designated by "FR-2"? | phenolic cotton paper | [
"Printed_circuit_board\n\nThere are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB indu... |
572fffeb947a6a140053cf3a | To what type of packaging is thermal expansion particularly critical? | ball grid array | [
"Printed_circuit_board\n\nThere are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB indu... |
572fffeb947a6a140053cf3b | What material delivers optimum dimensional stability? | glass fiber | [
"Printed_circuit_board\n\nThere are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB indu... |
572fffeb947a6a140053cf3c | What dielectric is matte glass and polyester? | FR-6 | [
"Printed_circuit_board\n\nThere are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB indu... |
57301001947a6a140053d018 | Along with the non-woven class, what makes up the reinforcement type materials? | woven | [
"Printed_circuit_board\n\nThe reinforcement type defines two major classes of materials - woven and non-woven. Woven reinforcements are cheaper, but the high dielectric constant of glass may not be favorable for many higher-frequency applications. The spatially nonhomogeneous structure also introduces local variati... |
57301001947a6a140053d019 | Which is the more expensive reinforcement type? | non-woven | [
"Printed_circuit_board\n\nThe reinforcement type defines two major classes of materials - woven and non-woven. Woven reinforcements are cheaper, but the high dielectric constant of glass may not be favorable for many higher-frequency applications. The spatially nonhomogeneous structure also introduces local variati... |
57301001947a6a140053d01a | What type of structure do woven reinforcements have that cause them to have variation in their electrical parameters? | spatially nonhomogeneous | [
"Printed_circuit_board\n\nThe reinforcement type defines two major classes of materials - woven and non-woven. Woven reinforcements are cheaper, but the high dielectric constant of glass may not be favorable for many higher-frequency applications. The spatially nonhomogeneous structure also introduces local variati... |
57301001947a6a140053d01b | Which ratio varies because of the structure of woven reinforcements? | resin/glass | [
"Printed_circuit_board\n\nThe reinforcement type defines two major classes of materials - woven and non-woven. Woven reinforcements are cheaper, but the high dielectric constant of glass may not be favorable for many higher-frequency applications. The spatially nonhomogeneous structure also introduces local variati... |
57301001947a6a140053d01c | For what kind of applications are non-woven reinforcement materials better than woven ones? | RF/analog | [
"Printed_circuit_board\n\nThe reinforcement type defines two major classes of materials - woven and non-woven. Woven reinforcements are cheaper, but the high dielectric constant of glass may not be favorable for many higher-frequency applications. The spatially nonhomogeneous structure also introduces local variati... |
57301192a23a5019007fcceb | What's the temperature at which resin softens and expands called? | glass transition temperature | [
"Printed_circuit_board\n\nAt the glass transition temperature the resin in the composite softens and significantly increases thermal expansion; exceeding Tg then exerts mechanical overload on the board components - e.g. the joints and the vias. Below Tg the thermal expansion of the resin roughly matches copper and ... |
57301192a23a5019007fccec | Along with vias, what makes up the components of a board? | joints | [
"Printed_circuit_board\n\nAt the glass transition temperature the resin in the composite softens and significantly increases thermal expansion; exceeding Tg then exerts mechanical overload on the board components - e.g. the joints and the vias. Below Tg the thermal expansion of the resin roughly matches copper and ... |
57301192a23a5019007fcced | What will happen to the components when the temperature of resin goes above that of glass transition? | mechanical overload | [
"Printed_circuit_board\n\nAt the glass transition temperature the resin in the composite softens and significantly increases thermal expansion; exceeding Tg then exerts mechanical overload on the board components - e.g. the joints and the vias. Below Tg the thermal expansion of the resin roughly matches copper and ... |
57301192a23a5019007fccee | When resin stays below Tg, its thermal expansion is similar to that of copper and what other material? | glass | [
"Printed_circuit_board\n\nAt the glass transition temperature the resin in the composite softens and significantly increases thermal expansion; exceeding Tg then exerts mechanical overload on the board components - e.g. the joints and the vias. Below Tg the thermal expansion of the resin roughly matches copper and ... |
57301192a23a5019007fccef | What do thick boards require to resist plating failure? | high Tg matrix | [
"Printed_circuit_board\n\nAt the glass transition temperature the resin in the composite softens and significantly increases thermal expansion; exceeding Tg then exerts mechanical overload on the board components - e.g. the joints and the vias. Below Tg the thermal expansion of the resin roughly matches copper and ... |
5730132704bcaa1900d7711d | What will happen to the materials when a board gets wet or is in a humid area? | Moisture absorption | [
"Printed_circuit_board\n\nMoisture absorption occurs when the material is exposed to high humidity or water. Both the resin and the reinforcement may absorb water; water may be also soaked by capillary forces through voids in the materials and along the reinforcement. Epoxies of the FR-4 materials aren't too suscep... |
5730132704bcaa1900d7711e | If materials absorb moisture and then are heated enough to vaporize the water, the board might show delamination or what other type of damage? | cracking | [
"Printed_circuit_board\n\nMoisture absorption occurs when the material is exposed to high humidity or water. Both the resin and the reinforcement may absorb water; water may be also soaked by capillary forces through voids in the materials and along the reinforcement. Epoxies of the FR-4 materials aren't too suscep... |
5730132704bcaa1900d7711f | What percentage absorption do F-4 epoxies have? | 0.15% | [
"Printed_circuit_board\n\nMoisture absorption occurs when the material is exposed to high humidity or water. Both the resin and the reinforcement may absorb water; water may be also soaked by capillary forces through voids in the materials and along the reinforcement. Epoxies of the FR-4 materials aren't too suscep... |
5730132704bcaa1900d77120 | What's the approximate relative dielectric constant of most materials in circuit boards? | 4 | [
"Printed_circuit_board\n\nMoisture absorption occurs when the material is exposed to high humidity or water. Both the resin and the reinforcement may absorb water; water may be also soaked by capillary forces through voids in the materials and along the reinforcement. Epoxies of the FR-4 materials aren't too suscep... |
5730132704bcaa1900d77121 | What material has an absorption rate of only 0.01%? | Teflon | [
"Printed_circuit_board\n\nMoisture absorption occurs when the material is exposed to high humidity or water. Both the resin and the reinforcement may absorb water; water may be also soaked by capillary forces through voids in the materials and along the reinforcement. Epoxies of the FR-4 materials aren't too suscep... |
57301519b2c2fd1400568827 | What's the minimum amount of copper a layer in a PCB can have to be considered "heavy copper"? | three ounces | [
"Printed_circuit_board\n\nThe printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carryi... |
57301519b2c2fd1400568828 | About how thick would a PCB layer be if it contained three oz. of copper? | 0.0042 inches | [
"Printed_circuit_board\n\nThe printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carryi... |
57301519b2c2fd1400568829 | What will a circuit board with heavy copper carry very well? | current | [
"Printed_circuit_board\n\nThe printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carryi... |
57301519b2c2fd140056882a | What would a PCB designer use heavy copper to make their circuit board resist? | thermal strains | [
"Printed_circuit_board\n\nThe printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carryi... |
57301519b2c2fd140056882b | Where does the heat go when it leaves heavy copper-plated vias? | external heat sinks | [
"Printed_circuit_board\n\nThe printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carryi... |
573016ea04bcaa1900d7715f | What arduous aspect of the process can designers skip in Multiwire? | routing of wires | [
"Printed_circuit_board\n\nSince it was quite easy to stack interconnections (wires) inside the embedding matrix, the approach allowed designers to forget completely about the routing of wires (usually a time-consuming operation of PCB design): Anywhere the designer needs a connection, the machine will draw a wire i... |
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