Question

5. s a de current and In the circuit shown in Fig. P e, is a sinusoidal signal. Capacitors C, and C, are very large; their function is to couple the signal to and from the diode but block the de current from flowing into the signal source or the load (not shown). Use the diode small-signal model to show that the signal component of the output voltage is V, If v, = 10mV, find v, for 1 = 1 mA, 0.1 mA, and I μ. Let R, = 1 kQ. At what value of 1 does v, become one-half of u,? Note that this circuit functions as a signal attenuator with the attenuation factor controlled by the value of the de current I Ci C2 ㄢ 굄 Figure P4 (Capacitors and constant current sources are equivalent to short circuits for AC signals)

Answer 1

n Civcoit i mal evalart Diode Smau imal model ys CL O VT 二 0.025 V R Rs RoAs RDRS Ven 0.035 시。 O 02S to I 0.25 X o D25 O 25 XlD t o25 045x 103 o.o26 O I25 0.2 39 mv = 9-615 mV

for Vo Vs 2. ·マ こ 0.DIS -6 5 2.5x16 -25 x 16 ‘