I never really dared to dig into electronics like this. I had a nack for breaking things when I did.

As an example, I purchased a Pentium machine back in the day. I had a feeling it was running too hot (or maybe I was trying to over-clock, I don't recall). But I decided to build a simple PCI card. So simple, in fact, that it just had a 12v case fan on it. I wired up the +12v pin and the ground pin to the 12v +/- of the fan. Then I plugged the PCI board into the PC. It worked! Except, it was now the only thing in the PC that worked.

After removing it, the machine no longer worked. I returned it to the shop I purchased it from and they informed me that I must have had a surge. Everything was destroyed. The CPU, the RAM, the Video card, it was all gone.