Electronics circuit calculation > LM317 R1, R2 calculation.


The LM117/LM217/LM317 are monolithic integrated circuit in TO-220, TO-220FP, TO-3 and D2PAK packages intended for use as positive adjustable voltage regulators. They are designed to supply more than 1.5A of load current with an output voltage adjustable over a 1.2 to 37V range. The nominal output voltage is selected by means of only a resistive divider, making the device exceptionally easy to use and eliminating the stocking of many fixed regulators.

LM317 circuit
VO = VREF (1 + R2/R1) + IADJ R2 VREF=1.25V, IADJ=50uA

VO =  Volt
Error =  Volt (Error voltage.)
Tolerance  5%    1% (Resistor tolerance)