So, one thing I've been reading about is Sparkfun's tutorial on transistors,focusing on BJT (specifically NPN, but a bit into PNP). I'm super new to transistors and such, so please bear with me.
Looking at the switch applications they all utilize an Arduino to provide control at the Base (LO/HI (0V/5V)).The first circuit concerns controlling an LED in the framework presented for Saturation mode ("On") and Cutoff mode ("Off"). Vc is at 5V.
VE > VB < VC; Drive the Arduino pin low, the transistor will be in Cutoff mode. VE < VB > VC; Drive the Arduino pin Hi, the transistor will be in Sat mode.
However, if VB = 5v, and Vc is 5V, wouldn't that violate the condition that Vb > Vc? Ve < Vb checks out, because Ve is on the GND side of the circuit.
They only mention that Vb has to be above a certain Vth to saturate the transistor (this part makes sense in that Vb - Ve > Vth), but leave out Vb > Vc.
Is it because Vc isn't really at 5V then due to voltage drops from the resistor and LED BEFORE the collector terminal???