How Does Cascading Common Emitter Transistors Affect Signal Amplification?

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yy.toh
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The ouput of common emitter transistor 1 is connected to input of common emitter transistor 2.
Please explain about the input and ouput signal (ac).
1.Is there any amplification after the transistor 1?
Normally the input is in uA, the output is in miliA
2.Is there any amplification after the transistor 2?
The output from transistor 1 is in miliA, how should it responsed by the transistor 2?
 
In the thumbnail, a 2-transistor common emitter (differential) amplifier is followed by an emitter follower (Q3). The first transistor (Q1) is a common-collector (emitter follower) current amplifier, and the second transistor (Q2) is a common-base voltage amplifier. A 10-mV input signal gives a 150 mV pulse out. Is this what you mean?

Bob S
 
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  • LTspice schematic of a differential amplifier with Q1, Q2 and Q3 NPN transistors, labelled Input pulse 10 mV 200 ns, Output pulse 150 mV into 50 ohms, with a plot below of V(vout3) rising to about 140 mV between 50 ns and 250 ns.
    Diff_Amp_2A.jpg
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