Last time, we'd got to a functional voltage regulator, with a pass transistor and op amp error amplifier but I cheated and used ideal voltages for the reference and op amp power supply.
This time I've sketched out a functional circuit using real parts found in the LTSpice library. I've chosen a rail-to-rail op amp to avoid problems with low voltage references. The LT1009 reference puts out 2.5 V, the op amp gain is 4, for an output of 10 V into 1 kohms.
Two versions of the circuit are included below. Voltageregulator5 has some additional RC filter stages to remove noise from the reference and op amp power supply Voltageregulator5b just takes everything straight from the input voltage. As you can see there's a fairly substantial advantage gained from judicial use of RC filtering.
So that's the end of Term 1. The basics have been covered, however briefly. I encourage you to download the LTSpice files and play...