Do you know what those hollow strip-shaped lines on a PCB are called? They are actually slot holes. Don’t underestimate this "slot" – it plays a crucial role in circuit safety.
 
When a PCB contains both high-voltage components and low-voltage components, they must be isolated. The standard practices are as follows:
 
1. No copper pouring is allowed on all layers of the high-voltage area.
2. There must be a clear dividing line between the high-voltage and low-voltage regions.
3. The minimum creepage distance must be maintained to prevent arc breakdown.
 
However, the problem arises when some designs are too compact to leave sufficient space. What should be done in such cases?
 
The most common and practical solution is – slot cutting. By cutting a slot on the PCB, the high-voltage and low-voltage regions are physically separated. This not only meets the safety distance requirement but also reduces the risk of breakdown. Therefore, slot holes are not just a "necessary compromise" in design, but also a key factor in ensuring the stable operation of high-voltage and low-voltage circuits.