ECE131_2008SPRING_EXAM3__[0] - "EI,.,.,.! ric:,l...

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"EI,.,.,.! ric:,l Fpginecrin:r, Depnrl !!lent The Cooper Union ECE 131A Solid-Stale Materials Devices Final Examination Spring 2008 1. The diodes 01 and 02 in the circuit given below are identical each with a cut-in voltage V y = a.7V, forward resistance rr = 0 and thennal voltage V( = 26 mV at room temperature. The lotal voltage vs(t) ~ V, + v,(I) where V, ~ lOY and v.(t) ~ 20sin(51) mV. IOkQ Dl + vs(t) D2 vo(t) 5kQ -L - -5V - a) Determine the slate of each of the diodes: forward or reverse biased. b) Obtain the equivalent small-signal (AC) model for the given circuit. e) Detennine the power associated with each of the diodes. d) Determine the expression for the tOlal voltage vo(t). 2. A uniformly doped silicon pllp bipolar junction transistor (BJT) with doping concentrations N n = IOIS/cm 3 , Nil = 5(1O'6)fcm 3 and N c = jQl5/ cm 3 at room temperature is shown below. p I~ t%o n I~ p ~ ~ , , , , x'=o x=o X=Xn x"=o E + ~.--- V E " ---~ •• - B - ••• ~-- V CJJ -----. ..;r + C The terminal voltages are Y
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This note was uploaded on 02/27/2012 for the course CHEMISTRY/ CH/ECE/PH/ taught by Professor Faculty during the Spring '08 term at Cooper Union.

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ECE131_2008SPRING_EXAM3__[0] - "EI,.,.,.! ric:,l...

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