The below drawn schematic of Op-amp 741 is configured in non-inverting mode with R1= 2 K Ω ,Rf = 20 K Ω , fo = 10 Hz & A = 400,000. Determine the following parameters :
1) Af
2)f F
a. 10.99 & 90.9 kHz
b. 10.99 & 36.36 kHz
c. 10.99 & 20 kHz
d. 10.99 & 10 kHz
Correct Answer : b. 10.99 & 36.36 kHz
Explanation : For non-inverting mode of an amplifier (voltage series feedback amplifier)
1) A
f = AB / 1+ AB
But, B = R1 / ( R1 + Rf) = 2 k / (2 k + 20 k)
= 1 / 11
1+ AB = 1 + 400000 x (1 / 11)
= 36364.6
A
f = 400000 / 3636.4 = 10.99
2) f
F = ( 1 + AB ) f
o = ( 36364.6 ) x 10Hz = 363646 = 36.36 KHz
