To ensure a constant 5V output from your 7805 voltage regulator, you'll want to use capacitors on both the input and output sides to improve stability and reduce noise. The 7805 datasheet typically recommends specific capacitor values for optimal performance, and while I can't access real-time databases for parts, I'll offer a standard recommendation based on typical applications. Here's what you'd usually see:

These values are typically effective for general applications, but your specific needs might vary based on the rest of your circuitry, such as the presence of large transient loads or RF sensitive circuits. It’s also a good idea to place these capacitors as close to the 7805 pins as possible to minimize any adverse effects of board layout on the regulator's performance.

If you have specific requirements or constraints (like size, temperature range, or voltage ratings) that need to be considered, please let me know, and we can refine these recommendations accordingly.