I have one more question to Boffin1's schematic.
I have tried with a emitter resistor at 5 Ohm and different supply voltages, and I get these results
Supply Voltage Collector current mA
3.8 280
4.5 310
7.6 450
I use a BC337 and to LED's on basis
Are these values as expected ?
I was hoping for a constant current independent of voltage to drive my 1W LED's