So I'm trying to learn some of the basics in electrical engineering such that I can better understand how computers work and I'm currently reading about circuits with switches, relays, different gates and how to produce different outputs based on inputs. I don't have a background in electrical engineering and this is the first book I've read related to this stuff so bear with me.
What I'm struggling with is this RS-latch. I understand the logic behind how the output is the input inverted and all that, and how to "activate" the different cords. I think that's basically what the circuit is meant to illustrate. However, what I don't understand is how the lightbulb is lit in this circuit. From my understanding there needs to be a closed circuit with a power source (battery) connected for the electrons to travel through the lightbulb to turn it on. Here, none of the batteries are connected to the circuit and the lightbulb is still lit.
What am I missing here? Is this just an illustration of how the concept of logic gates work and not a complete circuit?