help with this question and i will rate you fast The figure below shows a curren

Question

help with this question and i will rate you fast

The figure below shows a current source. Find the reference current, Iref. and the current Io. given VBei = 0.6V. When solving for Iref. use VBei =VBE2- Also, neglect the effect of beta and VA (i.e., assume the base currents IB1 and IB2 to be zero so that IREf = Ici = Iei- and ignore the change in Io with change in VCE2). Hint: Solve for Iref given Iref = Ici = Iei and VBEi = 0.6V. To find Io, write expressions for VB1 and VB2 and equate them (since VB1 = VB2 as since the bases are tied together). Use VBEI VBE2 to find the relationship between Iref and Io. Note: This method of using re sis tot's tied to the emitters of Q1 and Q2 is used to make current sources from discrete, unmatched transistors.

Explanation / Answer

I_ref = (Vcc-Vbe1) / R =(0-0.6)/10k = I_c1+I_b1+I_b2

but given

I_b1=I_b2 =0

Vbe1 = Vcc - I_ref*Rc - I_e1*Re+ Vee

but Iref= Ie1

apply kcl at Vee junction we get Ie2= I_0 since ib2=0

so Iref = (0.6+10-0)/11k = 10.6/11k

Vbe2 = Vee-I_0*Ro

Ro= 500 ohms

but

Vbe1=Vbe2

so

-10+Io*500 = 0-10.6-10

io= -10.6/500 = -21.2 milli amps

current gain = Io/Iref = 11k*21.2*10^-3/10.6 = 2

current gain =2

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