I got this low power transistor that I want to make a class-A amplifier out of, but I'm having a really hard time with it. It seems not to behave much like what I expect from a transistor.
The transistor came in a TO-126 package. I've never seen one like it, so I had no idea which side was the emitter. To figure this out, I tried to build a switching circuit.
When I unplug the base resistor going to the Vcc (+12 V), I expect Q1 to stop conducting. It doesn't though. I thought maybe I messed up the orientation. Flipping it around, however, did nothing. It does not matter how I wire it.
I replaced it with a 2N3904, and that worked just as I expected. The LED starts off not being lit. Then I hit the NO switch, and it lights up. But in the circuit above, it doesn't matter what I do, the circuit is always on.
What gives guys? Why can't I use this transistor as a switch?