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ELECTRONICS - [Calculators] - [LM317 calculator]

LM317 calculator

The LM317 is a voltage controller that can output a stabilized voltage. The voltage is determined by the chosen values of resistors R1 and R2. With the use of my calculator you can find out the required value for your application.

image of a standard LM317 application

You need to enter 2 known values. You can enter the value of both resistors to find out the output voltage. You can also enter the output value and the value of one resistor, to find out the second resistor. You should play a little bit with the values, to find out existing resistors in the E12/E24/... range.

A typical value for resistor R1 would be 220 Ohm.

Resistor R1 (Ohm)
Resistor R2 (Ohm)
Output voltage (V):

Ignore error term.

What with the error term?

The error term is a small signal from the ADJ pin of the controller. It is a very small current of 50 - 100 ľA. It doesn't influence the results much.

Copyright ©1998-2017 Vanderhaegen Bart - last modified: August 24, 2013