Hi, I would like to know what kind of values or things should I check in a darlinton datasheet for an arduino / 5V / 3V project?. I don't have any project in mind but I would like to use those with arduino and others 3.3/5V ICs. PNP and NPN. I'm buying some things and I wouldn't like spend money in something which is not going to work.
Why do you think you will need Darlingtons? General purpose BJT's like 2N3904 and 2N2222A are far more common in projects, and you can make a custom Darlington with two of them, if you are stuck for one.
Because I'm learning electronics and I would like to have a "real" darlington on my hands to compare with. I mean, I could build a darlinton with two BJTs but I would like to have a "good reference" when something goes wrong.
Max voltage, max current and dissipation - otherwise there's nothing interesting really, they are all similar in performance and behaviour. They all have a gain around 1000, and drop 1V or more for Vsat and are all slow (this can preclude PWM)