Is there anyone experienced with 7805, which input is supplied by switching power supply ? I use +12 V from regular PC power supply. Just now, it went broken. Is it wrong to use switching PS for 7805 input ?
That should work with no problem.
But maybe the dissipation was to much. 12 to 5 volt with let's say 0.5A is 7 (12V-5V)x0.5A =3.5W dissipation. That is a lot of heat. (cooling!)
Use capacitors at the input and output close to the gnd of the 7805. These are used to make the 7805 always stable. See data sheets for best value's . (most of the time 1µF - 10µF Tantalium)