Analzying transistor's help

Thread Starter

integralx2

Joined Sep 27, 2008
8
I have a question about analyzing a small signal transistor.
First Scenario:

Lets say i only have 1 transistor model shown. A common-collector. Lets say it has a load attached RL. Now which method is better to use. Do i unload the the RL find the Av gain of the transistor unloaded , then use the RL to find the overall Avs ? Or do i just keep it there?
 

steveb

Joined Jul 3, 2008
2,431
I have a question about analyzing a small signal transistor.
First Scenario:

Lets say i only have 1 transistor model shown. A common-collector. Lets say it has a load attached RL. Now which method is better to use. Do i unload the the RL find the Av gain of the transistor unloaded , then use the RL to find the overall Avs ? Or do i just keep it there?
It would be easier to answer if you post the circuit schematic.

Including RL is usually safer, but there is better flexibility if you calculate unloaded gain and the output impedance, and then include the loading effect in the total loaded gain calculation. The thing that is unclear is whether the RL is AC or DC coupled. If the RL is DC coupled, it can affect the DC bias point which can change the calculated gain and output impedance.
 
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