The electrical teacher tells the design points of the circuit board

To realize the function of an electrical appliance, engineers need to make circuit drawings before handing over the documents to the http://www.wcxpcb.com/ circuit board. Finally, the components are processed on the circuit board to form a functional product heart. The circuit drawing work is the most important. This paper is based on the years of design experience of electric master.

The pin span of the element should correspond to the pin hole of the insert. In particular, bulky components such as high voltage capacitors, relays and fuses to ensure that components can be installed in place.

The 2 elements are not soldered at the solder surface as far as possible, so that the welding efficiency is low and the copper peel is easy to be removed.

The edge of the wiring of the three components shall be more than 2mm away from the edge of the circuit board. It is easy to cause the copper skin off the circuit board during the process.

4. The three pins of the triode are as elongated as possible. If small or small, it is easy to cause wave soldering without tin.

When the cartridge element is inserted into the circuit board, the element body will not reach the edge of the circuit board. This will affect the assembly of the product, while making it easy to touch and cause the welding disc to fall off.

In the process of component placement, it is not possible to occupy the space between ontology and ontology. In the case of the triode and the field effect tube, it can be squeezed at each other in the interpolation, thus causing the copper peel or functional failure.

When connecting, use as few lines as possible. The connection mode of plug wire and socket can improve the efficiency.

The wiring of the circuit board should not be too thin. At the same time, there is a certain distance between walking and walking. The bias can easily cause the circuit board itself to be maltreated, and the circuit board itself opens; It is easy to short-circuit wire connections between lines.

9 all SMT elements should be surrounded by white paint blocks to block the tin line, so as not to short-circuit the tin, the appearance is beautiful.

Don't have too many flying threads on the 10 circuit board.

11 boost IC, patch triode, and patch 4007, the IN41418 welding plate of boseal tube is not too small, and the element cannot be directly pressed to the welding disc.

A white oil line is added between the welded plates when the pin is in a tight position, otherwise it is easy to cause the phenomenon of tin.

If there is a line under the patch, try to get away from the position of the welding disc as far as possible. Otherwise, it is easy to cause a short circuit. Try not to pass two walking lines at the same time.

Special components, such as CBB 104 capacitance, are too close. But the volume of the component is outside of the symbol, causing the components to be squeezed between the components, making it easy to make the copper breaking.

15. The welding disc of the plug-in element should not be too close to the chip element, otherwise it will be easy to cause the patch component to fall off when welding the assembly element.

As far as possible, the welds with the insertion are as high as possible. Try not to take the tin position, and use the white oil line between the welding plates.

Try not to walk too long in layout.

It is easy to break the welding disk at the position of the potentiometer and apply copper to the edge of the welding plate.

The welding disc of the power cord shall not be too small, and a mechanical layer shall be added on both sides of the welding disk to strengthen the mechanical strength of the welding plate, especially the welding disc which needs to be threaded.

The size of the pin and the hole position are not matched. It is the reason for the increase of the amount of the plug-in and the pre-welding work. The hole size should be appropriate.

The 21 element arrangement must not have any shadow, otherwise, it will cause a lot of virtual welding, circuit plateplate and jigsaw, and should be careful to consider the direction of wave soldering.

After the engineers have to collage, they can send out the sample file, paying special attention to the setting of the counterpoint origin of the surface element, namely MARK point.

The commonly used platen size is about 100~150mm wide, and the length is not limited, with 4~6 groups as appropriate, convenient for the production of assembly line.

When the PCB board is ordered in large quantities, the PCB board is best to open the die pressing plate to ensure that the holes are in the design dimension error.