What are the principles for pcb manufacturers to determine special components?

The following principles should be observed when determining the location of special components:

　　 (1) Shorten the wiring between high-frequency components as much as possible, try to reduce their distribution parameters and mutual electromagnetic interference. Components that are susceptible to interference should not be too close to each other, and input and output components should be kept as far away as possible.

　　 (2) There may be a high potential difference between some components or wires. The distance between them should be increased to avoid accidental short circuits caused by discharge. The components with high voltage should be arranged as far as possible in places that are not easily reachable by hands during debugging.

　　(3) Components weighing more than 15g should be fixed with brackets and then welded. Those components that are large, heavy, and generate a lot of heat should not be installed on the printed circuit board, but should be installed on the chassis bottom plate of the whole machine, and the heat dissipation problem should be considered. Thermal components should be far away from heating components.

　　(4) For the layout of adjustable components such as potentiometers, adjustable inductors, variable capacitors, micro switches, etc., the structural requirements of the whole machine should be considered. If it is adjusted inside the machine, it should be placed on the printed circuit board where it is convenient for adjustment; if it is adjusted outside the machine, its position should match the position of the adjustment knob on the chassis panel.

　　(5) The position occupied by the positioning hole of the printed board and the fixed bracket should be reserved.