Routing components on a PCB is a crucial stage in circuit design, directly influencing the circuit’s performance, stability, and production costs. A well-thought-out layout of components can shorten trace lengths, minimize signal delays, reduce electromagnetic interference, and enhance the circuit's ability to resist interference. It can also optimize heat dissipation and mitigate overheating issues on the board. While routing components, we need to consider not only the electrical aspects but also the mechanical structure and manufacturing processes. Here are some common routing principles:

1. The spacing between different networks is determined by factors like electrical insulation, manufacturing processes, and component sizes. Spacing settings should also consider the manufacturer's capabilities. Electrical insulation is particularly important if there’s a significant potential difference between two components or networks. This becomes even more critical when high-voltage and low-voltage circuits coexist on the same board, necessitating careful attention to ensure sufficient safety clearances.
2. The shape of circuit turns should be carefully chosen to make the board easier to manufacture and more visually appealing. Options include 45°, 90° angles, and arcs, with sharp corners generally avoided. Connections between wires and pads should be smooth to prevent small sharp points from forming. When a wire runs between two pads without connecting to them, it should maintain the maximum and equal distance from both pads. Similarly, the spacing between wires should be evenly spaced and maximized.
3. Trace width depends on factors such as the current passing through the wire and interference resistance. The higher the current, the wider the trace should be. Generally, power lines should be wider than signal lines. To stabilize the ground potential and minimize the impact of ground current fluctuations, the ground line should also be wider. Within the allowable board area and density, wider traces should be used to reduce circuit impedance and improve interference resistance. For power and ground lines, to ensure waveform stability, they should be thickened as much as possible when routing space allows. Typically, a minimum width of 50 mils is required.
4. Interference and electromagnetic shielding of printed circuit traces: Interference on the traces primarily includes interference between traces, interference from power lines, and crosstalk between signal lines. Proper arrangement and layout of the traces, along with appropriate grounding methods, can effectively reduce interference sources and improve the electromagnetic compatibility (EMC) performance of the circuit board. For high-frequency or critical signal lines, such as clock signal lines, the trace should be as wide as possible. Additionally, shielding can be applied by enclosing the signal line with a ground line, essentially creating a closed ground shield around the signal line to isolate it from surrounding signal lines.
5. High-frequency or critical signal lines, like clock signal lines, should have as wide a trace as possible. Shielding can be achieved by enclosing the signal line with a ground line, creating a closed ground shield that acts as an isolation layer, preventing interference from nearby signal lines.
6. A single via introduces about 10pF of parasitic capacitance, which can be detrimental in high-speed circuits. Excessive vias can also reduce the mechanical strength of the board. Therefore, during routing, the number of vias should be minimized. Moreover, when using through-hole vias, pads are often used as alternatives. This is because, during manufacturing, some through-hole vias may not be drilled completely due to processing errors, while pads are guaranteed to be drilled through, ensuring a more reliable manufacturing process.

The above are general principles for PCB routing, but in practice, the routing of components remains a highly flexible process. These principles serve merely as guidelines, with real-world experience being the ultimate test of their effectiveness.