can anyone explain to me when there is no need to have any resistor in the collector circuit of the two npn BJT differential pairs? The two BJT shares the same resistor in the emitter part and each of them have their own base resistors.

be the way the circuit is supposed to be a level dector....

Thanks a lot

 

Hi,

Can you post up the circuit? Not all differential pairs are alike.

 

The 47K resistor is the collector resistor for T1. Think of T2 as a common collector amp.