power supply damaged my arduino

Hello,

i connected my Arduino Leonardo to this power supply:

after few seconds i heard crack noise and arduino turned off (all lights turned off)

now, when i connect leonardo to usb cable, two LED diods next to barrel jack still shining and device is not detected by computer (in linux dmsg there is no activity on USB), last uploaded script in arduino is not running

arduino is probably dead, but i want to know, why this happened, i thought that parameters on power supply are OK for using with arduino

thanks

ondra

That supply is probably not regulated. There could be much more than 12 V on the output. Have you measured the supply output voltage?

If it doens't say it's a switching power source, then it's not regulated, and when there is no load on this kind of sources voltage reaches easily 15-18V (I've measured by myself). I had the same trouble you had (I bricked an Arduino UNO) and I learned my lesson, when using unregulated 12V I use an external voltage regulator LM7805, and only use the on-board regulator when using switching 9V source.

ok, for a next time, i'll watch for something with regulation:) now i cannot measure real output voltage on supply which destroy my device, but i will do it late. thanks