PCB Electrical Characteristics Check Item:

1) Is the wire resistance, inductance, and capacitance effects analyzed, especially for the critical voltage drop?

2) Is the spacing and shape of the wire accessories conforming to the insulation requirements?

3) Is the insulation resistance value controlled and defined at the key

4) Is the polarity fully recognized?

5) from the geometric point of view of the wire spacing on the leakage resistance, the voltage of the shadow?

6) Is the medium that changes the surface coating been identified?

PCB physical characteristics Check items:

1) Are all pads and their locations suitable for assembly?

2) Does the assembled printed circuit board meet the impact and vibration conditions?

3) What is the spacing of the specified standard elements?

4) Is it hard to install unstable components or heavier parts?

5) Is the heat sink cooling properly or is it isolated from printed circuit boards and other thermal elements?

6) Is the voltage divider and other multi-lead elements positioned correctly?

7) Is the component arrangement and orientation easy to check?

8) Do you eliminate all possible interference on the printed circuit board and throughout the printed circuit board assembly?

9) Is the positioning hole correct?

10) Is the tolerance complete and reasonable?

11) Control and signed the physical properties of all coatings No?

12) Is the hole and lead diameter ratio within the acceptable range?

PCB Mechanical Design Factors:

Although the printed circuit board is mechanically supported by the component, it can not be used as a structural part of the entire device. In the printed version of the edge of the part, at least every 5 inches for a certain degree of support. The factors that must be considered for the selection and design of printed circuit boards are as follows:

1) Printed circuit board structure - size and shape.

2) the type of mechanical accessory and plug (seat) required.

3) circuit and other circuits and environmental conditions of adaptability.

4) Depending on factors such as heating and dust, consider installing the printed circuit board vertically or horizontally.

5) Some environmental factors that require special attention, such as heat dissipation, ventilation, shock, vibration, humidity. Dust, salt spray and radiation.

6) the degree of support.

7) keep and fix.

8) easy to take down.

PCB printed circuit board installation requirements:

At least one inch of the edge of the three edges of the printed circuit board. According to practical experience, the thickness of the printed circuit board with a thickness of 0.031-0.062 inch shall be at least 4 inches apart; a printed circuit board with a thickness greater than 0.093 inch shall have a support point spacing of at least 5 inches. Take this measure to improve the rigidity of the printed circuit board and to damage the resonant circuit that may appear on the printed circuit board.

Some printed circuit boards usually have to consider the following factors in order to determine the installation techniques they use.

1) Printed circuit board size and shape.

2) input and output terminal number.

3) Equipment space available.

4) the desired loading and unloading convenience.

5) Type of attachment installed.

6) required heat dissipation.

7) the required shielding.

8) the type of circuit and the relationship with other circuits.

Printed circuit board requirements:

1) Area of ​​printed circuit board that does not require mounting of components.

2) The effect of the plugging tool on the installation distance between two printed circuit boards.

3) In the printed circuit board design to be specially prepared to install holes and slots.

4) When the plug tool is to be used in the device, it is especially necessary to consider its size.

5) A plug-in device is required, which is normally permanently attached to the printed circuit board assembly with rivets.

6) In the mounting rack of printed circuit boards, special designs such as load bearing flanges are required.

7) The adaptability of the size, shape and thickness of the plugging tool and printed circuit board used.

8) The cost involved in the use of the plug-in tool, both the price of the tool and the increased expenditure.

9) In order to tighten and use the plugging tool, it is required to enter the equipment to a certain extent.