BJT AC Analysis using r_e model
@ John Cena

The derivative of the deltaV_diode / deltaI_diode (the AC resistance, the 're', what I call the 'reac', and 1/tranconductance) is:

26 ohms if the DC diode current is 1 milliamp

260 ohms if the DC diode current is 0.1 milliamp

2,600 ohms if 0.01mA (10uA)