my basic problem is that my input to the transistor is a Voltage source.
How to know what current goes in to the base?

 

How do i control the current goint into the the base .
I saw a lecture summoned bellow but its very different from my circuit
how can i see the current mechanism of this circuit?
Thanks.

 

Emitter-follower: The emitter follows the base (minus 0.7V of the base-emitter diode) so if the base goes high then the emitter also goes high.
If the base goes low then the emitter tries to go low if there is a load at the emitter of an NPN transistor to ground.
You were showing the base having 0V to only +1V or +2V. Since the base never went high then the emitter also never went high.

Beta is not used for a saturated transistor switch. Betta is used for an amplifier transistor that always has plenty of Vce.
For a saturated transistor the base current should be 1/10th the collector current.

 

How to calcultage the base current in such configuration?
Thanks.

 

An emitter-follower never saturates (but maybe if its base us driven higher than the supply voltage).
Then its hFE (beta) and its emitter load current determine its base current.The beta is a range if numbers si would pick the minimum shown on its datasheet, add a load and calculate a few base resistor values to get close to how high the emitter voltage goes.