I'm experimenting with a simple transistor/LED circuit but after reading many articles online I still can't tell if I have a faulty transistor or things are working as expected.
Power source = 5V DC out of an Arduino 5V pin. Transistor data sheet: https://www.sparkfun.com/datasheets/Components/2N3904.pdf
Here are the scenarios and related questions;
LED flickers like a candle, transistor gets extremely hot. The data sheet says transistor can put up with 6 volts at a minimum right? So why does not having a resistor to the base make this happen? My understanding was that excessive current is not damaging as long as voltage is kept in order? I'm only using 5 volts.
LED flashes upon connecting the wires then turns off. Transistor not getting hot, not sure what's going on.
LED turns on normally, as if it's connected to the circuit with no transistor.
LED turns on but it's dimmer. I'm assuming this is related to the voltage drop characteristics of a transistor explained here? Base current and Vce relation in NPN transistor output characteristics
Does everything mentioned above sound normal?