Hello, could some check if I've got what I've already done is right and help me find Rin.
The question asks to find the voltage gains (Vc/Vs) and (Ve/Vs) and the equivalent input resistance as seen by the signal source for the BJT circuit which is biased to operate as a linear small signal ac amplifier, pictured below.
It is assumed that Cb, R1 and R2 are sufficiently large that they can be ignored.
The hybrid parameters for the BJT are;
hfe=50
hie=1.5kΩ
hre=hoe=0
And external resistors are:
Rb = 500Ω
Re = 50Ω
Rc = 6kΩ
(
My answer:
Vc/Vs = (-hfe*Rc)/(Rs + hfe*Re) = (-50*6k)/(500 + 50*50) = 100
Ve/Vs = (hfe*Re)/(Rs + hie + hfe' *Re) = (-50*50)/(500 + 1.5k + 100*50) = 0.8333
Rin = I'm not quite sure how to work this out.
EDIT: also this won't be marked it is merely a tutorial.
The question asks to find the voltage gains (Vc/Vs) and (Ve/Vs) and the equivalent input resistance as seen by the signal source for the BJT circuit which is biased to operate as a linear small signal ac amplifier, pictured below.
It is assumed that Cb, R1 and R2 are sufficiently large that they can be ignored.
The hybrid parameters for the BJT are;
hfe=50
hie=1.5kΩ
hre=hoe=0
And external resistors are:
Rb = 500Ω
Re = 50Ω
Rc = 6kΩ
(
My answer:
Vc/Vs = (-hfe*Rc)/(Rs + hfe*Re) = (-50*6k)/(500 + 50*50) = 100
Ve/Vs = (hfe*Re)/(Rs + hie + hfe' *Re) = (-50*50)/(500 + 1.5k + 100*50) = 0.8333
Rin = I'm not quite sure how to work this out.
EDIT: also this won't be marked it is merely a tutorial.
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