When we need to apply capacitor devices in circuit principles, we should choose appropriate capacitor devices according to the actual usage scenarios and requirements. When choosing SMD y capacitors and plug-in y capacitors, the following aspects should be considered:

1. Use location: If you need to use capacitor devices on a circuit board, it is recommended to use SMD y capacitors; if you need to manually solder the circuit board, it is recommended to use plug-in y capacitors.

2. Capacity requirements: If a small-capacity capacitor is required, it is recommended to use a SMD y capacitor, and if a large-capacity or high-quality capacitor is required, it is recommended to use a plug-in y capacitor.
3. Circuit working environment: If you need to work in a high-humidity environment, it is recommended to use a SMD y capacitor. If you need to work in extreme working environments such as high temperature and high voltage, it is recommended to use a plug-in y capacitor.