http://img528.imageshack.us/img528/3466/schematiccharkz4.png (included schematic and characteristic)
-The amplifier uses a BJT whose characteristic I provided has a different load line.-
The amplifiers load line connects between 4 mA on the Ic axis and 8 V on Vce. The amplifiers operating point occurs where the load line crosses Ib = 20 microA.
-Rc = 8V / 4mA = 2000 ohms
Vcc = 2mA * 2000 ohms + 4V = 8V
Rb = (8-.7)/20 microA = 365000 ohms
Given a small signal input:
What would be the net resistance in the signal input ciruit, the amplitude of the base signal current, the max. and min values of the total base current and collector voltage, and the gain of the amplifier?
Small signal:
Signal amplitude = 3mV
source resistance = 4KOhms
Transistors AC beta = 150
Transistors re = 40 ohms
Coupling capacitor = 1 microF
Signal frequency = 1 MHz
I am working on this one... So far I was wondering if using the equation for Rin = 1/(1/R1+ 1Rb) would be correct??
1/(1/365KOhms + 1/4Kohms) = 3956.64 Ohms?? I think I am way off though..
is the amplitude of the base signal current: Ib = (Vcc-.7)/Rb?? that seems incorrect to me..
would the voltage gain be Av = -Rc/Re => -2KOhms/40 Ohms = -50 Ohms??
Shouldn't that figure in somehow?
Do you know how to find the beta for the transistor from the load line?
Have you seen or heard of the hybrid pi model yet?