[warning]Careful! Don’t let the smoke out![/warning]
Hopefully you’ve never ruined any electronics device due to applying too much power. Some people have (cough, cough .. the voice of experience) and when this happens the device or component goes up in smoke. In popular jargon it is said to have “lost its smoke“.
When working with various components, always check their voltage ratings and make sure the input voltage does not exceed those limits. Also, even with correct voltages, if certain components are wired wrong (like polarized capacitors) they can still be damaged.
So it pays to always double check things before you hit that power on button!