On a shunt regulator, when the output voltage is larger, it has to increase the power to the transistor.
That is why the op amps are connected opposite ways round.
On point 3, the op amp output is many times the difference between the two inputs (pin 2 and pin 3). The op amp will have a gain of a million or more, so in normal operation, pins 2 and 3 will be at the same voltage.
If pins 2 and 3 are not at the same voltage, the output of the op amp will be either maximum or minimum.[/QUOTE]
CAN YOU EXPLAIN IT IN A BETTER WAY?