You can use this calculator to vary the value of the program resistor (R1) and calculate the output current for the LM317 / LM338 / LM350 family of three terminal adjustable regulators. This calculator will work for adjustable regulators with a reference voltage (VREF) of 1.25.
Read more source:http://diyaudioprojects.com/Technical/Voltage-Regulator/index.htm
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