This question already has an answer here:
If you want to describe something in general, which article do you use "a ―"(singular), "―s"(plural) or "the ―"?
A dog is obedient to its owner.
Dogs are obedient to their owner.
The dog is obedient to its owner.
I think "dogs" is better than "a dog" because there are many obedient dogs in the world, but I don't know whether "the dog" is correct or not in this case.
But I've seen this sentence:
The phonograph was invented in 1887 by Edison.
I think "phonographs" is also correct, but I'm not sure.