How do I set the lm317 voltage regulator to only output 1.2v?

I have a 1.2v regulator (lm317) and I have a circuit that is producing about 3v. How do I connect the two together so that I have a 1.2v output?

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110100101108 years ago
you can get 1.25 V if you connect it as if it was a 7805 if you really need exactly 1.2 V set it to 1.9 V and kill 0.7 V on a diode
fullcircle (author)  110100101108 years ago
Hello! Just wanted to thank you for taking the time to help me with this question! I appreciate it! Thomas
frollard8 years ago
Please don't forget to mark your questions as 'answered' if you got a good enough answer - or ask for clarification!
frollard8 years ago
http://www.cpemma.co.uk/317calc.html

yay google. Also - an lm317 is a variable output regulator for around 35 max volts in.

Lets you solve for the output voltage you want, or 'what will I get with this setup' format. Trouble is - this regulator isn't happy to produce less than 1.3 volts, regardless of setup.

Is your voltage source constant? Do you need regulated output? Using a series resistor would drop the 1.8 volts pretty easy...
fullcircle (author)  frollard8 years ago
Hello! Just wanted to thank you for taking the time to help me with this question! I appreciate it! Thomas