[SOLVED] Low output current from LM338 voltage regulator

[micktosin]

Hello there, i have a LM338 voltage regulator i designed and built, however the output of this regulator is in n-Amps. iTried so many circuit suggestion online and tested it in multisim the same problem persist. My question is based on the attached diagram, what i'm i doing wrong? I am trying to get an output of 5Amps at 29Volts which proves impossible.

 

[tpetar]

How you connect R2 ? R2 is not connected properly.
What is that mess at Probe1 place ?

Make this circuit better, this looks like very bad for eyes.

LM338K works very well, and can supply full continuous current of 5A and 7,5A in peaks in real life.

Check datasheet for specification and conditions.

Check maximum input voltage and power dissipation conditions in datasheet.

 

[IanP]

As it is, R2 shows the current drawn by the input of the meter, so 1nA seems to be OK.
Place R2 in series with the load ...
:wink:
IanP

 

[micktosin]

Thanks for the suggestions, it's now working after playing with the resistor values. However for understanding sake, can you guys please show me how to calculate the resistors values using the attached schematic below, for instance if i want an output voltage pf 28.8Volts. I still can't get figure out how to calculate the resistor based on the spec sheet.

 

[tpetar]

You can find formula in datasheet for Vout.

**broken link removed**



Here is calculator:
https://diyaudioprojects.com/Technical/Voltage-Regulator/

 

[micktosin]

Thanks a lot.