/diy/ - Do It Yourself

this is an AND gate used to charge a FET gate where the source could be between 0v and 30v below logic ground. the slow charge and discharge times are a benefit here. pretend the diode isn't there. why is it that when i cut off the top transistor while the bottom is still pulled to ground, current backflows through the bottom transistor out of the gate until it reaches 0v? aren't collectors supposed to be very low leakage?