BJT Small-Signal Models
• h-parameter model
– More complex
– Better for ac operation
– Common Emitter model
• hie = input impedance (Ω)
• hre = reverse voltage
transfer ratio (unitless)
• hfe = forward current
transfer ratio (unitless)
• hoe = output admittance (S)
ib
iC
B
hie
hfeib
1/hoe
hreVce
ie
E