I have now gotten it to work again
I had to build myself a new IC adaptor, this time I used a component adaptor, soldered the correct IC legs directly to it and bonded plus/minus-inputs, the adaptor got rigid.
Then I tried it out connecting all three OPs as voltage followers and injected a voltage of half Vcc, they all seemed to work.
After some modifications on the board, where I wanted to check the bias over the base current generating resistor and even made it possible to adjust it, I pushed the adaptor in place.
Then I did some measurements and I grounded the Us so that the voltage over the current generating resistor would be steadily measureable (ideally zero with no Us signal).
Then I mounted a trimmer over the resistor that controls the bias "adding" and by tuning that trimmer I got down from 0,8V offset to 0,1V offset (I left it at that because my LED refrences are not ideal when it comes to a supply voltage variation from 7V to 18V, which is my plan).
Remember that a 0,8V offset means an offset base current bias of 0,8/1k=0,8mA and while each step of the Us is 0,5V/10=50mV and thus 50mV/1k=50uA of base current, 0,8V offset is a lot!
So I trimmed this and got some fascinating results!
I am however sceptical that this is true but it seems like the BC546B actually compresses signal when it is driven around its maximum Ic current (that is, the hfe seems to be less than at midpoint Ic-wise).
I don't know if this is true but I hope so beacause otherwise my KTT just stinks
Can it really be that this is correct?
Some saturation feature when Ic-current gets too high?
But eaven the Earley Voltage looks strange now so I guess I am doing something wrong.
My two oscilloscope plots shows that when perfecly trimmed, exactly all eleven traces are visible but the high current performance is questionable, in the other plot I have "bueried" some traces in "zero" so that not all are visible but it looks better, I have made this plot by "faulty" trimmig like above.
Best regards, Roger
If I'm not mistaken, I seem to remember that BJTs has the highest hfe at a point somewhere inbetween their "lowest" and highest working collector current.
I have now uploaded a datasheet on BC546B and ACTUALLY hfe dives sharply after some 30mA, the highest trace in my plot being some 80mA.