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Step 2Calculating the Values
The following formula will allow you to calculate the resistor values to set the LM317 to any voltage that you need:
R2=R1((V/1.25)-1)
A standard R1 Value is 240 Ohms, so the final formula is:
R2=240((V/1.25)-1)
I chose the following power values for my power supply:
1.5
3
3.3
4.8
5
6
9
12
So my resistor values are the following(some have two for greater precision):
47
330
390
680
330 390
820 100
1500
1800 270
All of these resistor values can be found in the Radioshack 500 Piece Carbon Film Resistor Assortment.
R2=R1((V/1.25)-1)
A standard R1 Value is 240 Ohms, so the final formula is:
R2=240((V/1.25)-1)
I chose the following power values for my power supply:
1.5
3
3.3
4.8
5
6
9
12
So my resistor values are the following(some have two for greater precision):
47
330
390
680
330 390
820 100
1500
1800 270
All of these resistor values can be found in the Radioshack 500 Piece Carbon Film Resistor Assortment.
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