I have to answer this question in front of the class tomorrow. Been struggling all weekend with no joy. Question: Determine the minimum and maximum loads currents for which the zener diode on the figure below will maintain regulation. What is the minimum RL that can be used. Vz=12v, Izk=3mA and Izm=90mA Please see attached image file. If I figure the circuit without the load, apparently this will tell me how much the circuit will draw from the 24V power supply. It will still be regulated. I don't understand this. I'm beginning to feel stupid. When I figure out a circuit with a supply/resistor/zener diode, am I treating this as though it is an ordinary diode in forward bias? And what exactly am I hoping to end up with? Please see diagram attached.