I'm slightly confused as to how an open collector works. When a logic low input, the NOT gate is high, turning on the transistor and allows the current to flow from collector, through the load to the emitter, which is connected to ground. In this condition, does the load operate? When a logic low high input, the NOT gate is low, turning off the transistor. So in this condition, the load doesn't operate? What is the need for the NOT gate?