In actual circuit, please ignore the 9k resistor between the OpAmp output and -ve pin.
The 9k resistor is placed there to overcome the limitation of EveryCircuit model issue. The resistor aims to kick start the feecback operations
Let me know if you can suggest any fix for Every Circuit OpAmp feedback issues
OPAMP = LM324
5.1V Zener = 1N4733a
NPN = 2N3904
Potentiometer = Bourns 3296W 10k trimmer
