If you’re installing a new doorbell, a remote controlled device makes for the simplest installation and doesn’t require any of the circuitry illustrated on this page. All that’s required is to mount the button near an exterior door and the chimes in a convenient, central location inside the house. No need to run wires or splice into household circuits, fresh batteries are all that’s required.
The wiring in this diagram is for adding a new light fixture to a switched receptacle, i.e. one that is hot only when a switch is on. These are commonly used to turn a table or floor lamp on and off from a wall switch.
At the switch, the other end of the black wire is connected to the bottom terminal on the switch and the black wire going to the new light is connected to the top terminal. The white wire from the receptacle is spliced to the white wire going to the light, it doesn’t connect to the switch in this diagram, but a new electronic switch will usually include a neutral wire connection. At the light the black wire connects to the hot terminal on the fixture and the white goes to the neutral terminal.
The plain wire is the hot. If the cord isn’t marked with a bead then the strands of wire will be different colors. In these cases the silver wire is the neutral and the brass colored wire is the hot. The plug on the lamp cord holds another clue to polarity with the wide prong being the neutral and the narrow one the hot. Older lamp cord will have prongs that are the same size. This is because polarity was not observed on electric lamps until the development of grounded circuits.