Pnp & Npn

Thread Starter

magdyfayad

Joined Aug 20, 2007
1
this is a first thread for me

I attached a file and contain one question , if posible answer it and explain in details the differencd between comon emitter ( transistor is good as a switch ) and common collector ( transistor not good as a switch ) and why transistor not good as a switch at common collector ??

you can look to the file attachement and describle please in details what are the differences betwenn Q1 , Q2 and between Q3 ,Q4 as i know Q3 , Q4 is not good as a switch , why ??

so i want to know what the voltage applied between the emitter and PLC input for Q3 ,Q4 in both cases Q3 , Q4 are on and are off


thanks
 

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