Drawing board diagram of printed circuit board.
1.The board drawing of the printed circuit plate is the layout wiring diagram, which determines the layout direction of the printed circuit board on the premise of the basic determination of the shape and size of the printed circuit board, and roughly arranges the position of the main components and the power cord and ground wire of the lead wire.
2.Draw the outer outline of the printed board.
1)Printed circuit boards are designed to be rectangular or rectangular in shape according to the case, with a scale of 1:1, 2:1 or 4:1 for drawing sketches on the grid paper. The 5-10mm safety distance is set aside around the printed circuit board, and no circuit diagram is drawn within the safe distance. Positioning holes for two printed circuit boards, leaving space for technical requirements.
2) Determine the direction of typesetting.
The layout direction refers to the general trend of the circuit on the printed circuit board from the front stage to the back stage. Typography can be from left to right or from right to left, which is the first problem to be solved in the design of printed circuit boards and wiring. In the design of printed circuit boards, always want to have a unified source and ground wire, power cord and ground wire and transistor had better maintain an optimal position, that is to say, the lead between them should be as short as possible.
3) Drawing a single line uncrossed map. The circuit schematic diagram is based on the signal flow and the function of the components in the way, so there are a lot of crossover phenomena in the schematic diagram, which has no effect on the reading diagram. It is not allowed to cross the wires in the printed circuit board. Therefore, after the layout direction is determined, the single line cross graph is then drawn. To make the wires not cross, you can solve the problem by rearranging the position and direction of the components. But in the more complex circuit, sometimes even the rearrangement of the element position can not completely avoid the problem of cross-traverse, then the "flying line" can be used to solve the problem. "Flying line" means to cut off one of the printed circuit board wires at the intersection and connect them from the element surface of the board with a short connection. In the actual design, only a small number of "flying lines" can be used to solve the problem of circuit wire crossing; otherwise, the design quality of printed circuit board will be affected.
The drawing of single line cross diagram is an important stage of manual design of printed circuit board. Beginners often can not draw a good one time, need to read the circuit diagram to draw many sketches slowly improve the distance between the holes and the connection between the holes is the shortest for the best.The printed wires attached to the components are then outlined according to the single line non-crossover diagram. When drawing printed conductors, attention should be paid to the shortest and less printed conductors, the arrangement of conductors should not be too dense, the corners of conductors should be inclined lines as far as possible, and if there is an angle between the conductors, The angle between the conductors should not be less than 90°; the arrangement of the conductors should make the components arranged neatly; do not use circular printed wires as far as possible; when the printed wire span is large, it can be solved by bifurcation or island. To achieve the above, we need to repeatedly adjust and modify the position and direction of the components in order to be able to realized.