op-amp series voltage regulator

in the op-amp series voltage regulator , what is the input setting , comparator , control element and measurement that con sist of the zener diode . BJT and op amp ...Vref ??
thnak you

 

[jbartos]

Suggestion: References:
1. Markus J., "Electronic Circuit Manual," McGraw-Hill, 1971
Reference 1 shows IC Voltage Raising Regulator with another reference to:
2. Gifford J.F., Markkula M., "Linear IC's: Part 5, Ins and Outs of Op Amps, Electronics, Nov. 27, 1967, pp 84-93.
3. Apparently, the setting is variable depending on the Zener Diode (e.g. N461) and microamplifier (e.g. 709) or a type of the voltage regulator, i.e. circuit type, see Reference 1 and its more recent edition.