Hi guys,

I do not know to solve this problem. If you know, please help!

For circuit from picture I need to calculate Vin. I have this known data:

Ic1=4*Ic2; Vcc=1.4V; Vref=1.1V; Vces=0.2V; Vbe=0.7V (when transistor conduct); Iee=100μA; β1=β2=100

Rb=10kΩ; Rc=1kΩ; Va1->inf. Va2->inf.

Image in attachment. And thanks in advance!

I do not know to solve this problem. If you know, please help!

For circuit from picture I need to calculate Vin. I have this known data:

Ic1=4*Ic2; Vcc=1.4V; Vref=1.1V; Vces=0.2V; Vbe=0.7V (when transistor conduct); Iee=100μA; β1=β2=100

Rb=10kΩ; Rc=1kΩ; Va1->inf. Va2->inf.

Image in attachment. And thanks in advance!