It’s not unusual for an old house to have an old doorbell lurking about somewhere that hasn’t worked in years. Fortunately, it’s likely a simple matter to get things back in working order. As illustrated in the above diagram, the parts of an old doorbell circuit include the bell, a button mounted at the door, and a battery somewhere in between the two.
This circuit diagram shows the wiring for a new receptacle outlet connected at a light fixture. The source at the fixture is always hot and a switch loop controls the light. New 2-wire cable runs from the fixture box to the new receptacle and the source hot, neutral, and ground are splice to it along with a pigtail back to the fixture circuit. With this arrangement the new receptacle is always hot.
This page contains diagrams to add a new electrical outlet to an existing circuit. Arrangements are included to use an existing receptacle circuit or lights and switch circuits as the source for a new wall outlet.
The neutral and ground wires for the circuit are connected to a bar along the side of the service panel box. The neutral and grounding bars in the box may be separate or, in the case of older service panels, the same bar may be used for both purposes.