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Electronic components in the order of the circuit board pin

In Electronic Infomation Category: E | on November 24,2011

For the vast majority of electronic components is concerned, they are all polar or solder pin is not wrong. Such as electrolytic capacitors, once the anti-welding, an explosion occurs when electricity. In general the use of automation to the material mechanical components for circuit board assembly, it will not appear in the wrong parts of the problem. However, due to manufacturers conditions and 74LCX574 datasheet and characteristics of components itself, not all components can be installed automatically mount or plug. Common need to manually placed a variety of surface mount transformers, connectors, TO package integrated circuits. These devices are still likely to be assembled wrong question. Repair is usually carried out manually, this part is prone to weld the reverse problem. It is essential to the positioning of components and 74LCX574 price and methods of pad and 74LCX574 suppliers and screen printing circuit board components correspond to a clarification.

1 capacitor

shown below for the through-hole aluminum electrolytic capacitors, generally through the length of the imprint on the feet and body to represent the positive and negative. For the positive long-legged, short legs negative. On the negative side of the shell in a white or other generally parallel to the pin stripes.

circuit board as shown in electrolytic capacitors is generally marked with polarity.

method is marked directly on the cathode side of a "+" sign. This method has the advantage of soldering is complete, check the polarity of the more convenient. The disadvantage is the area occupied by the larger board. The second method is to use the screen to fill the areas where negative real. This polar representation board area occupied by small, but welding is completed, check the polarity is not convenient, common in the computer motherboard and other devices are high density circuit board applications.

through holes in the tantalum capacitor is usually marked on the positive side of the body "+" sign, and some varieties also used to further distinguish between the length of the foot.

this capacitor circuit board labeling method can refer to the aluminum electrolytic capacitors.

for surface-mount aluminum electrolytic capacitors. Is ink coated on one side of the negative real, positive side of the base is generally Notch processing.

it is generally in the circuit board as shown above

is in the circuit board with silk screen "+" sign indicates positive, while drawing the outline of the device came out. This has the side cutting angle can also be used to identify positive.

for surface-mount tantalum capacitors in terms of

it is generally in the circuit board as shown above

of the three capacitors in the left negative, right is positive. An indication of the most middle of the image.

2, diode

for light-emitting diode, the length of the foot is generally used to indicate positive and negative, positive long legs, short leg is negative. Sometimes manufacturers will be in the side of light-emitting diode, cut a little, this can also be used to indicate negative.

circuit board is generally used silk screen "+" means positive.

for ordinary diode

image above left is negative, the right side is positive, that the use of screen printing or stained glass to represent the positive and negative polarity. Circuit boards are commonly used in two ways, said positive and negative polarity.

circuit board with a screen to represent the polarity of the diode. This comparison image. Another one is the diode schematic symbol painted on the screen directly to the circuit board.

polar surface-mount LEDs that method is very confusing. Sometimes a manufacturer between the different package types that are varied. However, in the light-emitting diode common cathode side coloring or coloring of the points. Also in the cathode side of the beveled corners.

ordinary surface mount diodes kind

ordinary surface mount diode is on the screen or using the body to represent the negative of the stained glass. Two diodes are on the left image above is negative. In the graphic representation on the board generally:

image above left for the cathode pad, right pad for the cathode.

3, IC

distributed on both sides for the pin DIP and SO packages of integrated circuits, generally at the top of the semi-circular notch to indicate the direction of the chip above the top of the left foot for the first chip First foot. Also useful for screen printing or laser at the top of a horizontal line to represent the fight.

in addition to the foot directly on the chip next to the body on the first screen dot or directly with the injection pressure in a pit.

there are also some integrated circuit starting in the first leg on the side of the body to cut a bevel, said.

circuit board in this type of integrated circuit symbols are generally used with a gap at the top of the graphic mark.

package for the Quad QFP, PLCC, BGA is concerned.

QFP package integrated circuits commonly used in the first foot on the body corresponding to the use of pits, silk screen dots, or screen printing depending on the model to determine the direction. Some cut off a corner using the method, said first leg, then counter-clockwise for the first leg. Note that sometimes appears on a single chip three pits, the pit is not a corner, lower right corresponds to the chip.

PLCC package because the body is relatively large, usually at the beginning of direct use in the first leg to said pit. Some also made the top left corner cutting chip processing.

PLCC package kind

BGA package in-kind

BGA package, apart from the lower left corner of the image above direct gold-plated copper foil with said first leg, but still seem to lack with the screen angle and concave dot points and the way in the first leg of the direction.

corresponding to the circuit board of the graphics are as follows

feet on the first screen printing using dot notation and cutaway handle.

4 other devices

in general by the physical positioning of the gap on the connector to control the direction. There is also the first to write a leg or near the triangle to represent the first foot. Other devices generally draw through the circuit board with the same kind of screen to avoid interpolation errors.

through-hole for the exclusion, generally in the circuit board with a screen up in the common way to represent the circle. Or near the foot of the first to write one.

order to standardize the components of the circuit board pad, screen printing, solder and other requirements, IPC organization issued two related to the standard, namely: IPC-7351 and IPC-SM -840. However, in actual use, the device with the direction of the IPC defined method of production of the devices are often in the direction of the marker device after soldering is often obscured by the body, not suitable for examination, should be adjusted according to actual component land pattern design.

In short, the physical separation of devices on the general length of the foot and the method of screen printing or coloring polarity said. IC is often used for pits, screen printing, gap, chipping, short side or directly in the manner directed for the first foot mark. Pad in the production of graphics, the general shape of the device should be drawn by as much as possible, while as much as possible to the device the shape and location-related information is reflected by the screen printing form, in order to avoid manual assembly, welding errors.

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