Determination of size and shape of 1.PCB

First of all, according to the mechanical st ♠ructure of the product. σ§↕When the space location is mor‍π♣e abundant, we should try to sele ∞¥ct a small area of PCB. Because the area is to​↑¶§o large, long printed lines, increased impedance,Ω♦ noise resistance, cost increase₹£♠&s, but also take full ≤λaccount of the components of hea÷βt dissipation and adjacent to the line, ♦↑≤easy to interference and o‌↑ther factors.

2. layout

Layout principle of special components

Shorten the connection between the h'λ•igh frequency components§‌≥  as much as possible, and try to reduce their d♣£≤↔istribution parameters and electromagnetic ∑≈∞♣interference between them. Vulnerable com¥λponents should not be too close to eac®•©•h other, and input and≥>β output components should be kept as f£$ar away as possible.

Second, some components 'δor wires may have higher potential d≥→✔£ifference, should increase the distanc♦∏¥e between them, so as not to discharge₹€ • lead to unexpected short circγπuit. The components with high volta≠♣¶↕ge shall be arranged as f™σar as possible when the hand is not←  touched at the time of debugging.

Parts weighing more than 15g sha$γ∞ll be fixed with brackets and welded. Tho♠↕©se large, heavy, and more heat components s<® λhould not be installed♣> on the printed boar↔αd, but should be installed in the chassi•✔δs of the whole machine chassis, and should c §∏onsider the problem of heat dissipation. Th>₹ ©e heat sensitive elemλ✔₩σent shall be away from t✔<he heating element.

For potentiometer, adjustable inductance c β£oil, variable capacitor, micro switch and ot'™≥her adjustable components layout, shoΩ∞uld consider the structure requireme×€∞δnts of the whole machine. If the machineΩ♦ is adjusted, it should π‌be placed on the top of the printed board for®& easy adjustment. If it is adjusted outsiλ∏♠de the machine, its position should be adjust✔±$ed to the position of÷α☆ the adjusting knob on the pa'βδ€nel of the machine case.

The location of the PCB positioning hole aλ ∏nd the retaining bracke$ t shall be set aside.