I found in practive ones above 4.5ma Q3x where hard to get into zone, and ones above 5.5ma hard to down into that range. It may be best to swap Q3x to see which works best, making sure you measured them all as specified in the build guide.
Did you try that with K369s or alike models? Me I had encountered instability with those especially if on breadboard and the G to S link is patch wire and not a short pin link. Also with different DMMs and leads if in series mode. It will not come up with a FLUKE 87V but it will with a UNI-T.
So, should I exchange my 9K1 to 6K2? I think I choosed something like 3,5 mA for Q3x but I can easily desolder it as well as R3x if higher values are prefered.
Cool. I did Q7+quartet first. Since current is low I can not just add singlehandingly measured LEDs to eachother but has to go up slightly in values.
First 4,62 mA Idss I tried with LEDs that individually measured 1,965, 1,971, 1,973 and 1,972. That quadruple that should end up on 7,88 at larger current here ended up on 7,72. So I exchanged the 1,965 with a 2,000 and a stable total ended up on 7,75 volts.
Same procedure with next 4,60 mA. There I ended up with 1,974, 1,970, 1,969 and 2,003 LEDs stabilizing at 7,75 V.
Measured over 18 V.
Now, the question is what will happen when Q3 starts to take some current. Maybe I should solder one diode with long pins to make it easily exchangable.
First 4,62 mA Idss I tried with LEDs that individually measured 1,965, 1,971, 1,973 and 1,972. That quadruple that should end up on 7,88 at larger current here ended up on 7,72. So I exchanged the 1,965 with a 2,000 and a stable total ended up on 7,75 volts.
Same procedure with next 4,60 mA. There I ended up with 1,974, 1,970, 1,969 and 2,003 LEDs stabilizing at 7,75 V.
Measured over 18 V.
Now, the question is what will happen when Q3 starts to take some current. Maybe I should solder one diode with long pins to make it easily exchangable.
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I don't have 2sk369
I did do high range of bl grade 2sk170 and many throughout the range of c grade lsk170, some exceeding 20mA Idss with their very high gm.
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I just noticed this:
That was with gate and source connected together. Where did the other 0.5V go? What was between the gate and source that would have dropped half a volt at a few mA of current?
That was with gate and source connected together. Where did the other 0.5V go? What was between the gate and source that would have dropped half a volt at a few mA of current?