串联型稳压电路如题8-18图所示。已知UI=18V，UBE=0.7V，β1=60，β2=80，UDZ=+4.3V，R1=300n，R2=200Ω，R3=400Ω，Rc2=4.9kΩ，求：(1)输出电压UO的调整范围；(2)负载RL上的最大电流IL,max；(3)VT1管的最大功耗PCM。
An invocation of the musical philosophy of John Cage is appropriate here: “The first question I ask myself when something doesn’t seem to be beautiful is why do I think it’s not beautiful. And very shortly you discover that there is no reason.” This quote has always haunted me ...