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Qucs / qucs

Qucs Project official mirror
http://qucs.sourceforge.net/
GNU General Public License v2.0
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LM317 models not working as expected #367

Closed ntavish closed 9 years ago

ntavish commented 9 years ago

Vin sweep Vout should be 2.5V, and it should settle above around Vin=5V

Parameter sweep on R2, with constant Vin also is not at all as expected.

guitorri commented 9 years ago

Can you put the schematic into a Gist, or somewhere we can have a look a it?

ntavish commented 9 years ago

https://gist.github.com/ntavish/952c281f78be632c9f7a

This isn't on the same computer, and probably an older version(0.0.15-1.1 version for ubuntu 12.04), but result is the same.

ra3xdh commented 9 years ago

I think it is bug on Qucs-library side. There are two models for LM317 in Qucs library. LM317K-2 is working as expected (2.5 V at output), LM317K-1 and LM337 give wrong result. @ntavish , You can use LM317K-2 to get proper result. lm317

in3otd commented 9 years ago

looking at the component netlist I have the impression that the ADJ and OUT connection were swapped; indeed when swapping them on the schematic the output voltage seems correct.

in3otd commented 9 years ago

BTW @ra3xdh , the LM337 is a negative voltage regulator, if you apply -12 V at its input it works as expected.

ra3xdh commented 9 years ago

Closed via #375.