Take a look at the diagram again. Please Register or Log in to view the hidden image! If the first transistor is activated that would create a relative "short" from the collector to the emitter. That would place ground on the resistor connected to the base of the second transistor. Then the input of the hall senzor has no effect on the activation of the second transistor, and it is actually the voltage divider from ground going through the emitter and collector of the first transistor that creates a voltage divider via the small resistance of the first transistor going up through the inductors to the power supply. Now we have the base going to a resistor that leads to ground in a voltage divider and the emitter directly connected to ground for the second transistor. The resistor would then create a small difference in voltage that would give the base of the second transistor the small negative bias it needs to turn on. Then when the first transistor is on the second will also be on as well. This is a really in depth description of the operation of current flow in this circuit. It seems like you could all make great use of this type of understanding.