Electronics > Projects, Designs, and Technical Stuff
Simple DIY Linear PSU
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xavier60:

--- Quote from: panoss on March 07, 2020, 08:32:51 am ---RL=10 Ohm, Q1 Vb= 7.12V   Ic=0A
RL=5   Ohm, Q1 Vb= 7.60V   Ic=0A

No current through Q1?? :-//

--- End quote ---
Q1's Collector current should be the same as the current through R10 witch can be calculated from its voltage drop.
I would also expect the op-amps to be allowing Q1's Base voltage to go up much closer to 9V. Check this.
Without knowing the current gain of the output transistors, I can't work out the expected maximum output current.
You can try lower values for R10 as a temporary fix.
Watch for stability problems.
kallek:
That .pdf file does not open. At least base current go through because voltage drop. Are you sure you are measuring dc current?
panoss:
kallek, the pdf file is not actually a pdf file but a pdsprj file: you have to change the .pdf to .pdsprj.
Yes, I'm measuring DC.

I changed the Amp Meter and now it shows current flow! (the other amp meter I used has a low resollution!!!):

RL=10 Ohm, Q1 Vb= 7.12V   Ic=0.00143A  Ve=6.45V
RL=5   Ohm, Q1 Vb= 7.60V   Ic=0.00189A  Ve=6.9V

panoss:

--- Quote from: xavier60 on March 07, 2020, 08:47:54 am ---Q1's Collector current should be the same as the current through R10

--- End quote ---

RL=5 Ohm, Q1: Ic=0A 0.00189A   IR10=0.00190A
kallek:
No I did not. I assume that then I need Proteus too. Currents looks like ok, the difference is probably base current. Next measure Q2 current to check if pass transistors get enough base current.
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