The symbol ● is indicated in the red circle, which represents that the two cables are connected. It does not mean to connect the wiring cable to the middle of the other cable. In this case, it means, after connecting the lower end of the fuse F and the red lamp C2, to connect the red lamp C2 to the contact on the left side of BS1.
It is feasible with two wiring cables.
Key point
The devices connected on the cable number 1 (lower end of fuse F, terminal of red lamp C2, and left terminal of BS1) have the same electric potential. "Electric potential" might not sound familiar, and thus is explained by comparing to water level as follows. Water flows from higher to lower water levels, but not at the same level. The current also flows from higher to lower potential.
Circuit diagram
Think about wiring.
The symbol ● is indicated in the red circle, which represents that the two cables are connected. It does not mean to connect the wiring cable to the middle of the other cable. In this case, it means, after connecting the lower end of the fuse F and the red lamp C2, to connect the red lamp C2 to the contact on the left side of BS1.
It is feasible with two wiring cables.
Key point
The devices connected on the cable number 1 (lower end of fuse F, terminal of red lamp C2, and left terminal of BS1) have the same electric potential. "Electric potential" might not sound familiar, and thus is explained by comparing to water level as follows. Water flows from higher to lower water levels, but not at the same level. The current also flows from higher to lower potential.