The tech schematics list numbers in the bottom-right corner of some components, but I can't figure out what their significance is. For example, the electric light schematic has a 10 in the box for filaments, but it only takes one filament to make it.

These numbers represent required expertise in corresponding technological discipline to be able to craft an item.

To add to this, you can get tech expertise in two ways: by investing points in the discipline, or by buying tech manuals for that college.

Since there are 7 levels per discipline, each skill point spent raises your percentage by around 14-15%. Each tech manual adds an amount equal to your intelligence*, and manuals do stack; but they're both expensive and heavy.

*Protip: if you're using the UAP (and you should be) drink a potion of Intelligence before attempting to craft the item; this will make each tech manual more powerful (up to +20 per manual) allowing you to get away with buying fewer manuals.

If you're NOT using the UAP, then drink a potion of Intelligence before BUYING the manuals (you have one real-time minute to buy as many as you need) and again upon using them. The vanilla (unpatched) version grants you a bonus equal to the lower of your IN level at purchase and use, which is kind of unfair.

No, that can't be right. You don't have to have ten levels in the Electricity discipline to make electric lights, but the schematic has a "10" in the space for filaments. I think you must not have understood what numbers I was talking about, so I've attached a screenshot to make it clearer. (The Arcanum wiki's page on Technological Disciplines lists the same numbers, but with no explanation whatsoever about what they mean.)

Okay, I think I get what you're saying now. I don't see what the point is of having two different numbers to represent the same thing, though. For that matter, why would the components have different numbers? It makes sense when you're talking about schematics you found or bought, which require expertise in two different disciplines, but not for the default schematics that you learn automatically.

However, I realize that these are really questions for the game's designers, and you probably can't answer them unless you have an inside track on what the designers were thinking. So, thanks for the information.

I suppose they're there just for the sake of consistency of graphical design, nothing more IMHO.