## What will be the values of bandwidth & maximum output voltage swing respectively in an non-inverting amplifier with input resistance of about 40 ohm, input capacitance of about 0.1 μ F with inclusive of R1=R2=R3=200 K Ω , Rf = 2 M Ω and Vcc= +20V?

a. 32.56 kHz & 20 Vpp

b. 30.56 kHz & 20 Vpp

c. 47.56 kHz & 20 Vpp

d. 67.56 kHz & 20 Vpp

Correct Answer : c. 47.56 kHz & 20 Vpp

**Explanation :**In accordance to given data, the ac input resistance of the amplifier can be given by,

R

_{if}= (R2)¦(R3) ¦ [R

_{i} (1+AB)]

When [R

_{i} (1+AB)] >>R2 or R3 then, the above equation becomes

R

_{if} ≈ (R2)¦(R3)

≈ 200K ¦ 200K

= 100K Ω

The low frequency cut-off limit can be exaggerated using

f

_{L} = 1 / [2 πC

_{i}(R

_{iF} + R

_{0})]

=1 / [2 π (0.1 x 10 -6) (100K +40 )]

= 62.8 Hz

The gain of an amplifier is = 1+ (Rf / R1)

= 1 + ( 2M / 100K)

= 21

From the formula of Unity gain bandwidth,

UGB = Af x FH

Therefore, fH = UGB / Af = 1 M / 21 = 47.61 Khz

Bandwidth = FH – FL = 47.61 Khz – 0.0476 KHz = 47.56 KHz &

Ideal Maximum Output Voltage Swing = +Vcc = +20Vpp.