1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution This is a solved example given in my Physics textbook . I am not understanding a couple of things . 1) How is Iin calculated as Vin/Rin ? Why is the book not taking potential difference between Base Emitter into consideration ? Instead shouldn't Kirchoff's Voltage rule be applied in the Base Emitter loop ? I think it should be Iin =( 1mV -VBE )/2KΩ 2) Shouldn't the diagram be showing Vout across 100kΩ ? I don't understand why book considers Vout to be VCE ? Please help me understand these issues ?