LM317 for variable current control?

[Lostgallifreyan]

Circuit idea for linear current control from zero amps to fixed maximum.


|¯¯¯¯¯¯¯¯¯¯¯| R1
¡-------| LM317 T |----/\/\/\----x----x------¡
¦ |___________| ¦ ¦ ¦
¦ ¦ ¦ ¦ ¦
x !------------¡ ¦ ¦ x
¦ VR1 ¦ _¦_C2
¡----/\/\/\----x
x R2 ¦ D1 D2 ¦ ¯¦¯ x
¦ ¡---/\/\/\---x---|<|--|<|---! ¦ ¦
¦ ¦ ¦ ¦
!------x--------------------------------x------!


VR1 10K Lin
R1 1R 2W
R2 10K
D1,D2 1N4001
C2 1000µF Electrolytic


I don't expect extreme accuracy from this, but could it work ok? Is it a
disaster waiting to happen? Comments welcome.

Can I expect to get close to maximum output if the R1 side of VR1 cannot
fall below 100 ohms, given a high enough R2 side for VR1? And if so, how
close, and how high might the total resistance for VR1 be allowed to go?