7 years in patent law. These days, I use my electro-mechanical skills to put food on the table, but that doesn't mean I've forgotten. If you're going to ask licensing fees to use someone elses art even in a device they never could have imagined it being used, it doesn't make their art yours. Best case scenario, you're splitting license fees with whomever holds rights to trim pots and voltage regulators (RCA and GM, probably). Worst case, RCA figures out you used their art for profit in a manufacturing process without paying them licensing fees... An idea on paper is very different than an idea that actually made it to manufacturing.
Again, more power to you. I hope you are successful. I don't know your time line (you said your app went in a year ago, but I have no idea when you began selling your devices nor when or if you discussed your idea in public), but you'll want to cover your ... as much as possible if you gave away your idea by sales or public discussion before the app went in. More so if anyone on any public forum helped you or made suggestions you tried out or that actually made it in to any production design.
Six maybe you missed the point, this is the application of variable voltage in a PV , because a pot exists has no bearing on it , it is the unique combination that is patent-able NOT the POT ! or the regulator BUT put them together and they are a patent-able device.
I have been doing this a long time and hold 10 patents many just like this one and they have proven to be very sturdy and enforceable.
Here is a quick list from the USPTO
PAT. NO. Title
1 7,461,415 Method and apparatus for automatically lifting a cover
2 6,989,895 Automated fiber optic inspection system
3 6,954,262 Automated fiber optic inspection system
4 6,454,631 Polishing apparatus and method
5 6,428,391 Method and apparatus for polishing
6 6,302,763 Apparatus for polishing
7 6,190,239 Polishing method using two stage members
8 6,183,343 Polishing apparatus with defined pattern
9 5,947,797 Computer-controlled method for polishing
10 5,319,734 Fiber optic attenuator