NPN bipolar transistor ( Early Effect)


A bipolar junction transistor (BJT or bipolar transistor) is a type of transistor that relies on the contact of two types of semiconductor for its operation. NPN is one of the two types of bipolar transistors, consisting of a layer of P-doped semiconductor (the “base”) between two N-doped layers. A small current entering the base is amplified to produce a large collector and emitter current. The DC emitter and collector currents in active mode are well modeled by an approximation to the Ebers–Moll model. As the collector–base voltage varies, the collector–base depletion region varies in size. This variation in base width often is called the “Early effect”. In the forward-active region, the Early effect modifies the collector current and the forward common emitter current gain.

Related formulas


ICThe collector current (A)
ISThe reverse saturation current (A)
VBEThe base–emitter voltage (V)
VTThe thermal voltage (V)
VCEThe collector–emitter voltage (V)
VAThe Early voltage (V)