random thoughts of an engineer

Protection circuitry Having all parts selected it was a high time to draw schematic. Let's start the discussion with the protection circuitry. All output rails have to be protected against reverse polarity. In case someone shorts positive and negative power rails together one over-current / short-circuit protection will turn converter off before the other one possibly leading to rail reversal. Protection is as simple as putting beefy Schottky diodes normally in reverse polarity on all 3 power rails. Another possibility is that the user connects 2 busboards together using ribbon and he doesn't connect 24V rail to one of them. In that case converters will be back powered. LMR50410 starts with pre-biased output without any issue but MAX1757* doesn't have clear specifications in this context. To protect it I decided to "create" 24V line from 12V and 5V lines using Schottky diodes from output to input of positive voltage converters, just like you protect linear regulat...

Background Thanks to help of my friends I managed to contact a very helpful PhD working at Warsaw University, Faculty of Physics that researches ultrafast laser pulses and their use. She got interested in my project and we spend over 6h measuring chlorophyll in various ways. Measurements Because 2 high school students also came to learn about spectroscopy we started with redoing excitation ans emission measurements. As expected we found 2 peaks at the excitation spectrum each came with corresponding 2 peaks in the emission spectrum.  Then we measured lifetimes of each of the transitions. 420nm excitation resulted in 5.36ns lifetime for both 672 and 729nm emission. 468nm excitation resulted in 2.94ns lifetime for 657nm emission and a double exponential decay for 716nm. This double decay was around 90% 2.94ns and around 10% 5.8ns.  As a sidenote: Generating sub 1ns, tunable laser pulses is "simple". It was just a matter of using  Q-switched Nd:YAG going through nonlinear cr...