This is probably a really stupid question, but it's got me confused. The circuit diagrams have grounds labelled, and these are typically the -ve or black wires that make their way back to the battery; correct?
There are also cases where the enclosure is referred to as a ground and is the third wire (green) from a three prong plug. It seems that we're not supposed to connect the enclosure and the -ve terminals interchangeably. Are they both really called ground? Am I confused for no reason?