I have +9v connected via 180 ohm resistor to the collector of an NPN transistor. The emitter is connected via 680 ohm resistor to the anode of an LED, with the cathode connected to ground.
If I allow a small current to flow into the base, the LED lights up and the voltmeter reads about +2V as I expected.
Here's the thing that doesn't make sense: with the base connected to nothing, I can touch the base with my finger to make the LED glow faintly. And when I measure the voltage across the LED in this circumstance, I find it reverse biased at -4v with one multimeter and -5v with a second multimeter. I'd love some one to explain this. Thanks.