Element arrangement rule
1. In usual conditions printed circuit board layout principle, all of the components shall be arranged in the printed circuit of the same side, only the top-level element is too close, to some height is limited and small heat devices, such as SMD resistor, SMD capacitors, IC, and other on the bottom.
. under the premise of ensuring the electrical property, components should be placed on the grid and parallel or vertical arrangement, in order to tidy and beautiful, and the general does not allow elements overlap; element is arranged to be compact, input and output elements as far apart as possible.
3 there may be a high potential difference between a component or a conductor, should increase their distance, so as to avoid accidental short circuit due to discharge and breakdown.
4 with high voltage components should be as far as possible in the commissioning of the hand is not easy to touch the place.
5 the component is located at the edge of the plate, at least 2 thickness of the plate is the distance from the edge of the plate.
The 6 element should be evenly distributed in the whole surface, uniform density.
2 according to the signal to the layout principle
1 usually in accordance with the signal process one by one to arrange the location of each functional circuit unit, the core components of each functional circuit as the center, around it for layout.
The layout of the 2 element should facilitate the signal flow, so that the signal can be kept in the same direction as much as possible. In most cases, the flow of the signal is arranged from left to right or from top to bottom.
In the end, the output directly connected components should be placed close to the input and output connector connector or place.
3 prevent electromagnetic interference
4 strong electromagnetic field components, as well as the electromagnetic induction of the more sensitive components, should increase the distance between them or to be shielded, the direction of the component placement should be cross with adjacent printed wiring.
2) as far as possible to avoid the high and low voltage devices mixed with each other, strong and weak signals of the device staggered together.
3). To produce a magnetic field component, such as a transformer, a loudspeaker, inductor, the layout should be pay attention to reduce the magnetic field lines cutting of the printed wiring of neighboring elements magnetic field direction corresponding
Perpendicular to each other, reducing the coupling between each other.
4) to shield the source of interference, shielding cover should be a good grounding.
5) in the high-frequency operation of the circuit, to consider the influence of the distribution parameters between the components.
4 restrain thermal interference
1) for heating elements, should be priority in the heat dissipation of the location, when necessary, can be set up a radiator or a small fan, to reduce the temperature, reduce the impact on neighboring components.
2) some large power consumption of the integrated block, large or medium power tubes, resistors and other components, to be arranged in a place easy to heat, and separated from the other components.
3. The thermal sensitive element should be close to the component and far away from the high temperature area, to avoid the impact of other heating elements, causing false action.
4) when the double-sided placement of components, the bottom of the general does not place the heating element.
5 adjustable component layout
For the potentiometer, variable capacitor, adjustable inductor coil or micro switch and other components of the layout should consider the structure requirements, if the machine outside the regulation, its location and regulation
The knob is adapted to the position of the cabinet panel; if the machine is adjusted, it should be placed in the place where the printed circuit board is adjusted.
Printed circuit board design
SMT circuit board is one of the indispensable components in the design of surface mount. The SMT circuit board is a supporting part of the circuit element and the device in the electronic product.
Electrical connection between devices. With the development of electronic technology, the volume of PCB board is smaller and smaller, the density is higher and higher, and the PCB plate layer is constantly increasing.
PCB requires more and more in the overall layout, anti-interference ability, technology and manufacturing.