LM317 is the most widely used IC, available from different manufacturers like National Semiconductors, Fairchild, ST Microsystems, etc. LM317 is a linear voltage regulator with the output in the range of 1.2V to 37V at around 1.5A. The output voltage is regulated with approx. 1% tolerance. It is a 3 terminal Integrated Circuit available in various packages. Here we will be having a look at T0-220, package which is a plastic package with inbuilt heat sink. 

Pinout Diagram of LM317

Circuit diagram: 

The Output Voltage is given by the equation, 

Vout = Vref(1 + R2/R1) + (Iadj.R2)

Vin - Vout Difference = 3V to 40V

Output Current Imax < 1.5A 

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