I have a control circuit which has multiple settings and may have any number of sensors attached to it (each with it\'s own set of settings). These sensors may only be used
The contents of a class should be the implementation details of that class. Are the nested classes implementation details of the outer class, or are you merely using the outer class as a convenient name scoping and discovery mechanism?
If the former, then you shouldn't be making the private implementation details publically available. Make them private if they are implementation details of the class.
If the latter, then you should be using namespaces, not outer classes, as your scoping and discovery mechanism.
Either way, public nested classes are a bad code smell. I'd want to have a very good reason to expose a nested class.