Constant Current Circuit

Can not see anything CONSTANT, here!!! Otherwise if you change the boulb resistance ( wattage) the brightness should remain unchanged.

you can see that the following link explain everything. Mr. Know-it-all !! https://patents.google.com/patent/US3114872?oq=3%2c114%2c872

This circuit works, even its overcomplicated. But the way you present it is missleading. Put a load into the collector of the PNP and you can demostrate the constant current @kiani does not noticed. Anyway, for a demostration of the principal its overengineered. It is not nessesary to have two time constant current sources cascaded to understand how it works. Some users like to hide there knowledge and this is a bad thing! Keep it readable and simple or you just demonstrate a bad side of your personality. Or is it yourself do not understand it and give a link to an external Mr Explain for me? Anyway, kiani had similar problems in describing his circuits so you both have to improve this.

Thx for link. Here is one for you, hope it,s usefull. http://everycircuit.com/circuit/5732916868153344

I don't know it all. But i know all of what i know.

@kiani, The poti position is set at coffee machine water heater power with 1440Watt. Why 120V to demonstrate a current source?

Here a more practical version http://everycircuit.com/circuit/4685019674312704

Cause ehen people see pots. They like to fidle with it to see what happens,. Plus a huge range of input voltage, if this doesn' t demonstrste the current is constant nothing will.