amplifier

If u want to simulate transistor action u can frget about two diodes. Completely uselss cuz if they need to work must share one midle layer and not create just pnnp assembly like u have here.

Transistor can be modeled using VCCS dependent source. But those give only image of transistor working in active mode. Transistor is in fact a nonlinear resistor whose change resistance in function of voltage that appear on emitter base junction. When chnge of this volage is higher than increase of EC voltage a resistance change is so high that for AC driving signal it give a negative dynamic resistance region and so on pltential divider formed from resistor and transistor an AC part of output in center of this voltage divider is magnified considerably when compared to ac part at input. BJT (and mosfet also) Transistor is unable to direct amplification of DC currents and voltages. It can only amplify AC part but it can never cross supplied DC equivalent . This what is say as Common emitter current amplification factor and stated as DC curent amplification is missleading information created so to make transistor easy in understand. Nowhere this current amlificaton takes place. Output of transistor give always less charges than comparable charges that are sourced directly by active sources into transistor. This current damp is measured in so called common base current gain factor alpha. This is physical current amplification factor of transistor and as u see BJT transistors have it allmost all less than one. Higher than one is achieved in other transistor types such as avalanche transistors (modern ones recently available) or point contact ones or in extremely rare four layer bjt trannies as only one exception in bjt family. Transistor should be considered rather as resistance ratio amplifer or as voltage controlled negative dynamic resistance device and this is most valid description. All amplification obtained is a negative dynamic resistance type of amplification and to learn more refer to basic principles of this type of amplifiers

tnx