Given the four statements, which of the following statements are not true about the operation of an op-amp? i. Op-amp's close loop operation employs negative feedback that takes portion of the output and applics it back out of phase with the input. ii. In an op-amp, amplification of the common input signals is much less than that of the opposite input signals. iii. In open-loop operation, the output of the op-amp is driven to saturation with Vo +Vsat. iv. Op-amp's close loop operation employs positive feedback that takes portion of the output and applies it back out of phase with the input. O i, III, IV O i, iv Oi i i O i,iv

i. The saturation voltage an op-amp is primarily controlled by(i) power supply (+Vcc and -Vcc)(ii) open-loop gain of the op-amp(iii) common mode gain (iv) slew rate

has been determined that a certain op-amp has three internal critical frequencies, as follow 1.2 kHz, 50 kHz, and 250 kHz. If the midrange open-loop gain is 100 dB, is the amplifier configuration stable, marginally stable, or unstable?

Figure 3 shows a Hartley oscillator. Assume that the op-amp employed in the figure is an ideal op-amp, and R1= 20 kΩ, R2 = 60 kΩ, L1=10 mH.  b) State the Barkhausen criterion for sustained oscillation.c) Explain briefly how the phase shift requirement for sustained oscillation ismet in the circuit of Figure 3.d) The feedback ratio and oscillation frequency of Figure 3 are givenrespectively by, B = -L2/L1 and w0 = 1 / sqrt(L1 +L2)C Determine the values of C and L2 in order for the circuit to oscillate at a frequency of 200 Hz.