Schrijver: GH van de Pol

Titel beoordeling: Works OK but watch out!

This is an awesome regulator, but it's MISSING a diode!

The LM317 module itself is fine, and the adjustment is stable. But there's no reverse-protection diode on the board! If you disconnect the input while the output cap is still charged, the output capacitor discharges backwards through the regulator from OUT to IN, and that reverse spike will eventually kill the pass transistor eg. a dead chip that just passes input straight to output (0 Ω across IN–OUT).

Easy fix: solder a diode from Vout to Vin. A 1N4007 is plenty; a 1N5408 works too if that's what you have. After adding it I've pulled the supply plug out hot plenty of times with zero issues.

So: good cheap module, just add that one diode and it'll survive real-world handling.