differential limiting amplifier

[mmzaj]

HI

i know that the circuit attached to this thread is a differential limiting amplifier , and the collector of Q2 acts as a current source , but other than that , i can't get my mind around it !! P1 is the input , P5 is the output , and Vcc is +12 connected to the 27 R .

could someone please walk me step by step on how to analyze (understand) this freakin Amp !!

 

[LvW]

The shown circuit resembles a common collector and a common base circuitry in series. Advantage: high input resistance compared with a common base arrangement alone. By the way: this circuiry is the base of the classical differential amplifier (long tailed pair).