Variable Current Limit with Steady Voltage

[ag273n]

several months ago, i created my variable power supply using an LM317 - it was working great and I have been using just about on every electronics experiment I do... but that PSU can only output 1.5A max and cannot limit the current output.

now i have the LM338 - which can do 7A max, and i want it to include a way to limit the current output (variable) with a steady output.
so how do you make a variable limit to the current draw - with the same voltage?


the above diagram is what i'm hoping to build...
i tried looking up online for any tutorials, but i could hardly find one thats worth reading...

 

[Audioguru]

When you limit the current then the voltage drops according to Ohm's Law.
A second LM338 can be used as a current limiter ahead of the voltage regulator. A current limiter and a current regulator are shown on the datasheet of the LM338.

 

[ag273n]

i found this from the datasheet:



so i'm guessing just connect this in series to the earlier schematic i have... correct?

 

[Audioguru]

i found this from the datasheet:

View attachment 32360

so i'm guessing just connect this in series to the earlier schematic i have... correct?

Of course. Probably ahead if the voltage regulator.
This current limiter has a voltage drop so the input voltage must add it to the voltage regulator input requirement.

 

[ag273n]

Thanks a lot