I am studying the current mirror circuit.
I already went through similar questions and answers on this forum. But I was unable to get clarity from the answers. I am just a beginner. I request if you can answer in simple terms in steps for my benefit. I myself had asked similar question but I was not able to understand the answers. I went back and tried to understand and still was not able to get clarity. So, please help.
- What is the purpose of using a diode connected BJT? Won't a normal Diode be sufficient in place of BJT?
I understand it is a very simple circuit but I am not able to understand how does this circuit establish current in Q1 and Q2 to be same?
Can someone explain me the basic concepts to help me understand this?
2.What is the necessity to establish a constant current using this method? Why can't we use a single transistor and control the Vbe and Ib of it to produce a constant current? Why do we need two transistors to complicate this? Please help me understand this.
3.While considering Q2, proper biasing is giving by Q1. Vbe of Q1 and Q2 are same. But should it mean that collector current of both the transistors are same? I understand that both are identical transistors in their geometry. But how does the current be same?
4.I also understand that Q1 must be in saturation and for Q2 to establish a constant current, Q2 should be in active region,right? So that, if the voltage Vout is increased,Q2 will vary its Vce to provide constant Iout. Is this correct?
Sorry for the long query. Please correct my concepts if I am wrong. Thank you all.