1
GATE ECE 2001
Subjective
+5
-0
Assume that the OP_AMP in the figure, ideal

(a) Obtain an expression for V0 in terms of Vs, R, and the reverse saturation current Is of the transiostor.

(b) If R = 1$$\Omega$$, Is = 1pA and the thermal voltage VT = 25mV, then what is the value of the output voltage V0 for an input voltage Vs = 1V?

(c) Suppose that the transistor in the feedback path is replaced by a p-n junction diode with a reverse saturation current of Is. The p-side of the diode is connected to node A and the n-side to node B. Then what is the expression for V0 in terms Vs, R and Is ?

2
GATE ECE 1997
Subjective
+5
-0
Consider the circuit given in fig. using an ideal operational Amplifier.

The characteristics of the diode are given by the relation I = Is $$\left[ {{e^{{{qV} \over {KT}}}} - 1} \right],$$

Where V is the forward voltage across the diode
(a)Express V0 as a function of Vi assuming Vi> 0.
(b)If R = 100K$$\Omega$$ , Is = 1$$\mu$$A and $${{KT} \over q}\,\, = \,\,25mV$$

3
GATE ECE 1995
Subjective
+5
-0
Shown that the system in Fig. is a double integrator. In other words, prove that the transfer gain is given by $${{{V_0}\left( s \right)} \over {{V_i}\left( s \right)}} = {1 \over {{{\left( {CRs} \right)}^2}}},$$ assume ideal OP -AMP
4
GATE ECE 1994
Subjective
+5
-0
Find the output voltage of the following circuit assuming ideal op-amp behavior.
EXAM MAP
Medical
NEET
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
CBSE
Class 12