It was only a matter of time until something blew up. And last night, it was TWO things.
The first one was my own darn fault – I’ve been playing around with some simple transistor amplifier circuits, and mis-read one of the transistor data sheets. When I hooked it up a 12V power source… BANG!
You can see the TO-220 package there, literally split in half by the power of electricity. Zam zam! Turned out I had grounded the emiter and applied 12V to the base of the transistor. It blew apart in my face in a shower of sparks.
So, I desoldered that transistor and replaced it with a little J110 FET I had a pile of from my last trip to California. While messing around with the supply voltage, I kept switching a clip lead back and forth between 5V coming out of the 5V rail on an arduino an 12V directly from and SLA battery. Unfortunately, at one point, I disconnected the clip from the circuit and ended up connecting the Arduino directly to 12V…
Update 2/29: I’ve toasted another one! I’ve been using my old Duemilanove to work on a transmitter project, and apparently relying on its little 5V regulator to power an LCD screen, an Si5351 breakout, and provide bias current to the finals was just too much for the little thing….