Common-Emitter Common-Base Common-Collector

Input Impedance Zin

Moderate

1 2R || R || rπ

Low

Em

1R || r ||

gπ

High

( )1 2 0 E LR R r 1 R Rπ + +β

Output Impedance Zout Moderate

CR

Moderate

CR

Low

1 2 SE

0

r R R RR

1π +

+β

Voltage Gain

i

outV

in

VA

V=

High Inverting

( )m C Lg R R−

High

( )m C Lg R R

Low < 1 ( )

( )0 E L

0 E L

1 R R

r 1 R Rπ

+β+ +β

Current Gain

i

out inI V

in L

I ZA = = A

I R

High Low < 1 High

Power Gain

i

2out out inP V

in in L

V I ZA = = A

V I R

High Moderate Moderate

Capacitor controlling ωL

CE

Cin

Cout

Capacitor controlling ωH

Cu (Miller Effect)

Cu Cu

Assuming rd = ∞