Two transistors drawing from the same current.

Chain of dependencies

,

Collector current by

Now small changes in Vce Results in no changes between terminals so the same model as 4.22 is used. Also changes in Vcb creates no changes.

Eq 4.9 now with the early effect

Differentiation of eq. 4.67 with respect to Vce yields slope

Large signal model changed to

For small signal model, controlled current source remains unchanged to gm is

Change in collector current with Δ Vce

Ro is the ouput resistance. Both that and rπ are inversely proportional to the bias current Ic

Summary of concepts studied thus far

Leads to a sharp rise in IB and fall in β

Eq 4.23-4.25 must be modified for pnp

Then to include the Early effect for pnp

Same as the npn model