00:01
It has been asked to find the input impedance of the given amplifier circuit.
00:14
So, the input impedance of an amplifier is the impedance experienced by the ac input source driving the input of the amplifier, which drives the input of the amplifier.
00:35
Now, in order to find the ac equivalent circuit, the ac equivalent circuit of the given circuit can be determined by replacing the dc voltages that is vcc to ground and by replacing the coupling capacitors c1 and c2 by effective shorts.
01:31
So, they might be sorted.
01:33
So, replaced by shorts.
01:36
So, if we do so, so this is one arm, the r parameter transistor model can be drawn.
02:02
So, this is the base, the transistor r parameter transistor model is that the transistor can be replaced by a current source.
02:14
This is rc, vcc is grounded and the current ic in the outer circuit is beta times ib.
02:24
This is the emitter arm, this is the base resistance, which is again grounded because vcc is grounded.
02:34
This is the input side and this is the output side.
02:38
We are interested in finding out the input impedance when we look into this block, while looking into this block...