Hi, I got the following problem for homework (attached), I solved it but wanted to double check the answer.

Please give it a try. Thanks.

[attachmentid=226]

 

Originally posted by ds_164@Nov 8 2004, 11:09 PM
Hi, I got the following problem for homework (attached), I solved it but wanted to double check the answer.

Please give it a try. Thanks.

[attachmentid=226]

[post=3458]Quoted post[/post]​

i think the noninverting input is A

apply a + vol to A and B grnd

as it is pnp the collector current prop to exp(vbe/vt) decreases say by dI
I biasing so , current thru B inc by dI

3A current source so current thru o/p trans of the second stage decreases by dI

VB-Vbe=constant at emitter of the o/p transistor of the second trans
so as current decreases Vce increases and o/p amp gain = +1 so o/p increases

+ at A => + at o/p
so A is non inverting