Here two receptacles in one box are wired using the device terminals. With this arrangement, if receptacle #1 fails, receptacle #2 may also fail if failure is due to physical damage. However, if the copper tab conductors between the terminals remain intact, even if #1 stops functioning, receptacle #2 will probably still work.
Here a gfci receptacle is added at the end of a row of duplex receptacles for single-location protection. The first outlet is connected to the source and 2-wire cable runs from box to box. All wires are spliced with a pigtail at the devices to pass current from one to the next. The load terminals on the gfci are not used and it does not protect the other receptacles in the circuit.
To wire a 3-way switch circuit that controls both the fan and the light, use this diagram. As with all 3-way circuits, the common on one switch is connected to the hot source wire from the circuit. The common on the second 3-way switch is connected to the hot wires on the fan/light.
Here 3-wire cable is run from a double-pole circuit breaker and split to supply 120 volts to two sets of receptacles. The neutral wire from the circuit is shared by both. This wiring is commonly used in a 20amp kitchen circuit where two appliance feeds are needed, such as for a refrigerator and a microwave in the same location.