random thoughts of an engineer

Task  Last summer I was asked to design busboard for 3U 42HP eurorack case. For those of you who have no idea what it is I explain. Eurorack system uses 10 (less common) or 16 (more common) pin IDC ribbon to transfer it's power. It requires symmetrical 12V and sometimes 5V. 1HP is 5.08mm so 42HP case roughly 213mm in size. source: doepfer.de Requirements As with all project I got set of requirements that contradicted each other partially: fit into shape of case, allocating space for 28 M2.5 mounting holes provide at least 0.8A on all 3 output rails, 1A on positive rials preferable lowest possible output noise single 24V input supply possibility of daisy chaining cooling to top side of PCB Initial plan First I started thinking that I can simply use linear regulators for 5V and 12V, but after finding out that I'd need to dissipate over 23W of heat worst case it became immediately obvious it's not the way to go. Case is plastic, without many ventilation holes and without force

 Dye Death  Regarding the experiment described in the last post. We tested 5 power levels : 0.1W, 0.2W, 0.4W, 0.8W and 1.6W with the same power * time product of 30 sW. All samples degraded the same, which suggests that it is a photochemical reaction and not a thermal decomposition. It's much better to see this in real life than on the photos, but for those that are curious I'll attach it below. Looking up in the appropriate literature the most probable explanation is an oxidation of molecules excited to triplet state by the oxygen dissolved in to the solution. This also explains why sample in basement held in such a good state. It was enclosed in flask with air tight, ground seal. extreme left and right are without the laser exposure, different power levels in between What's interesting though, is that the dye died above, as well as at the level of laser beam but not below. This means that the amount of heat generated is enough for the convection in order to mix the fluid