Basics

A device that produces nitric acid from air, water, and a large amount of electricity (The Birkeland–Eyde Process)
Energy ineficient but very simple and only requires things (minus the electricity) that are almost everywhere

Used For

Production of Nitric Acid for Use As Nitric Acid
Production of Nitric Acid for the purpose of converting it into other fixed nitrogen compounds, for fertilizers (as a reserve/for emergencies + special cases not widespread inneficient use) without the tie to petrochemicals

The Birkeland–Eyde Process Has Fallen Out Of Most Use
It Has Been Replaced by the Ostwald Process (In conjunction with the Haber Process typically for the the production of the ammonia feedstock)
These processes require though things such as complex catalysts, very high pressures, and a continious source of hydrogen (which is often fossil fuel based)
The problems mentioned above are not as bad for large scale, but they don't make much sense at a small to medium scale
Also if an area has an excess of electricity due to cheap methods of electricity generation, the inefficiencies aren't as bad

Cody(from youtube's "Cody's Lab)'s design, it is a bit rough but if refined using digital fabriction technologies, it could work very well]
This design from the youtube channel "Puddin" seems like a slightly cleaned up version of Cody's Design
This design from the youtube channel "acroduster uses some nice glassware. We could contact the creator if intested in more documentation.
This design from the youtube channel "herbert Bodelstein" uses magnets to "spread" the electric arc. Not essential but may increase efficiency.]