.net pdf 417

.net pdf 417

.net pdf 417

.net pdf 417

datamatrix net example, code 128 vb.net free, how to create barcode in vb.net 2010, .net barcode printing, truetype tot.net code 128, code 39 nvidia nforce networking controller, vb net gs1 128, .net pdf 417, asp.net code 39 barcode, .net pdf 417, asp.net ean 13, .net ean 13, upc internet recenze, qr code generator using vb.net, .net ean 128

asp.net mvc 5 pdf, pdf.js mvc example, asp.net mvc 5 create pdf, mvc print pdf, asp.net pdf viewer component, how to upload pdf file in database using asp.net c#

.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,
.net pdf 417,

1 Through-Hole Technology By and large, the repair and/or rework of through-hole solder joints still uses hand-soldering procedures (see Fig 4030) In the case of a repair procedure, the first step is to add flux and solder to the joint Then the soldering iron is contacted to the lead, thereby allowing the solder to reflow The tip should be removed from the joint as soon as possible to prevent excessive heat conduction up the lead and into the component, where it may damage the active (Si chip) device(s), glass-to-metal seals, etc..

FIGURE 40.30 Hand-soldering techniques using point, tweezers, and hot-bar tips to perform repair or rework procedures. (Courtesy of OK International and Electronic Products and Technologies.)

In the case of rework procedures, the most difficult step is often de-soldering the damaged component for the latter s removal from the circuit board In the case of axial leaded devices, it may be possible to cut the leads of the damaged component The component can then be removed from the circuit board, thereby increasing access to the joint area for the de-soldering operation Lead-cutting is more difficult for radial leaded and high-pin-count components such as DIPs, PGAs, and connectors due to their shorter lead lengths and limited clearances between the package and circuit board surface Typically, the operator must remove the solder from the joint, usually one joint at a time, to release the component.

excel ean 13 font, winforms pdf 417 reader, asp.net data matrix reader, barcode generator for ssrs, crystal reports upc-a, crystal reports ean 128

A light coating of flux is applied to the Cu braid; the braid is then placed between the fillet and the soldering iron, with preference given to resting the tip near the top of the fillet, against the lead This technique limits possible damage to the Cu pad, solder mask, or laminate Sufficient solder must be removed from each joint so that the component can be extracted with minimum force to prevent damage to the Cu barrel or the Cu pad The dressing of the through-hole and Cu pad is the next step An excess of solder remaining in the hole will hinder lead insertion for the new component It is difficult to extract physically all solder residue form inside a hole, even at modest aspect ratios (board thickness-to-hole diameter).

t

This difficulty is further compounded with thicker, multilayer circuit boards because the soldering iron tip cannot compensate for the large thermal mass of the laminate or the heat-sink effects caused by the internal Cu layers Finally, it is often necessary to contact the Cu pads of the circuit board briefly, with the braid between the pad and the tip, to remove any excessive solder residue Soldering of the replacement component on to the circuit board has fewer complications than does part removal Using a hand-soldering process, after the device has been inserted into the circuit board, each joint is made one at a time The operator provides real-time inspection of the joint for any defects Finally, if necessary, flux residues can be removed from the circuit board using the appropriate cleaning procedures.

Thicker, multilayer boards are more difficult to solder due to their greater thermal mass and the heat-sink effects of the internal layers Preheating of the circuit board can be used to augment the soldering iron heat source Typically, the circuit board is heated to a temperature in the range of 100 to 125 C However, because the preheating step is applied to a full-up.

Frequency range: 2.0 to 60 MHz Initial frequency tolerance: .5% Frequency Stability: .3% Frequency aging: .3% over 10 years time

assembly (minus the defective part), consideration must be given to the heat sensitivity of other components on the circuit board Preheating with a hot plate may be acceptable for some applications However, when temperature-sensitive components are nearby, other heating methods such as hot-air (gas) sources may be required to localize the temperature rise away from other components or structures Several techniques can be used to assist with the hand-soldering process (de-soldering or re-soldering), or even substitute for it altogether For example, there is equipment that can heat multiple joints at a timeThe so-called hot-bar technique is a soldering iron with a long bar for the tip The bar simultaneously heats up a row of leads for the de-soldering or re-soldering step.

Hot air or hot gas guns can provide more diffuse heat sources that can melt all of a component s solder joints at the same time, thereby facilitating the removal and replacement of larger components that have a greater number of I/Os Selective soldering, or solder fountains that perform like miniature wave-soldering machines, are an effective approach for the de-soldering and re-soldering of through-hole components In fact, this technique is particularly well suited for connectors The thermal energy provided by the molten solder fountain can overcome the heat-sinking effects of the connector structure and thick, multilayer circuit boards However, it may be necessary to preheat particularly thick circuit boards (>30 mm) having multiple internal layers in order to melt the solder joints of a defective product successfully, as well as to achieve hole fill and adequate fillets on the replacement part.

(a) Supply pressure (Po Pa) 4 3 d d* 2 1

birt code 39, asp.net core barcode scanner, .net core qr code reader, birt ean 128