The in-vehicle ECU needs to operate normally with fluctuations in its power supply (Vbat) (6V to 18V). This is a power supply for quantitatively testing with arbitrary tr/tf (dv/dt) reproducibility. Although not for in-vehicle use, the stability of DC/DC converters and their contradictory transient characteristics (i.e., phase characteristics) are very important, so I created this for phase characteristic evaluation, but I am selling it now that the evaluation is complete. It can also be used as a regular (manually voltage-set) experimental stabilized power supply. (Maximum 18V/2.5A) Introduced on Youtube: <https://www.youtube.com/watch?v=lxQvB_FjG6I> There are no noticeable scratches, but it is handmade.