LM317 / LM338 / LM350 Current Regulator Calculator
LM317 / LM338 / LM350 Current Regulator Calculator
You can use this Current Regulator Calculator to vary the value of the program resistor (R1) and calculate the output current from the LM317 / LM338 / LM350 family of three terminal adjustable regulators. This Current Regulator Calculator will work for all adjustable integrated circuit regulators with a reference voltage (VREF) of 1.25. For more information about these voltage regulators, see the LM317 / LM338 / LM350 Voltage Regulator Calculator, Information and Circuits page.
Figure 2: LM317 / LM338 / LM350 Current Regulator Calculator Schematic
LM317 / LM338 / LM350 Current Regulator Calculator
To determine the output current from the regulator, enter a value for the program resistor (R1) in ohms and press the "Calculate" button. This will calculate the Output Current in Amperes and the amount of Power Dissipated across R1 in Watts.
NOTE: this online current regulator calculator requires that JavaScript be enabled on your browser.
LM317 / LM338 / LM350 Current Regulator Calculator
UPDATE - the LM317 / LM338 / LM350 voltage regulator calculator has been moved to it's own page, LM317 / LM338 / LM350 Voltage Regulator Calculator. Please update your bookmarks.
Datasheets - LM317 / LM338 / LM350 3-Terminal Adjustable Regulator
- LM117 / LM317A / LM317 Adjustable Regulator Datasheet - (PDF 1MB) - March 2010 - National Semiconductor
- LM138 / LM338 5 Amp 3-Terminal Adjustable Regulator Datasheet - (PDF 400kB) - May 1998 - National Semiconductor
- LM150 / LM350 3 Amp 3-Terminal Adjustable Regulator Datasheet - (PDF 400kB) - May 1998 - National Semiconductor
LM317 / LM338 / LM350 Current Regulator Circuits
The following circuits show some of the basic uses of the LM317 / LM338 / LM350 series of voltage regulators when configured as a current regulator or constant current source (CCS).
Figure 2: 1 Amp Current Regulator Schematic for LM317 / LM338 / LM350
Figure 3: Precision Current Limiter Schematic for LM317 / LM338 / LM350
Figure 4: 50mA Constant Current Battery Charger Schematic for LM317
Voltage Regulator Links
- LM317 / LM338 / LM350 Voltage Regulator Calculator, Information and Circuits
- Simple Low Resistance Test Jig with LM317 - [external link]
- The Care and Feeding of LM317 and LR8 Integrated Circuit Regulators, Particularly in Valve Circuits