Lm317

Thread Starter

1-3-2-4

Joined Dec 26, 2008
199
I have a 18V input and I need a 12V output, in the datasheet they list this

VO= 1.25 V (1+R2/R1)+I ADJ R2

I was wondering if a 100K pot on the adjustment pin was enough range to get to 12V

So if I do something like 100 ohm on R1 and 100k on R2 I should have around 12V? 860 ohm is .86K right?
 

PackratKing

Joined Jul 13, 2008
847
Google " Pot shunt " ... It is possible to reduce a 5K pot to some lesser value, at a slight-to-severe loss of linearity... depending on how far afield you go with the parallel resistor.. bear in mind that [ check on this ] you place the parallel resistor on the pots element -- Not the wiper... and draw your voltage off the wiper as you normally would...

That based on the Ohms Law that states two 1000Ω resistors in parallel will net approx 500 Ω\

Juggling, is an art that is worth learning :D
 
Last edited:
Top