The Electrician
- Joined Oct 9, 2007
- 2,970
What is the point of this post? This is exactly what tnk already described in post #3.the ac input Z calculation is very similar to the dc input Z calculation, with the exception that under high enough frequency, Re1 is shorted and Re2 is shorted for ac purposes.
so your input impedance will just be the divider resistors + the beta amplified Re resistors (for ac purposes), all in parallel.