Question

. Consider a voltage amplifier having a frequency response of the low-

pass STC type with a dc gain of 60 dB and a 3-dB frequency of 1000

Hz. Find the gain in dB at f = 10 Hz

Answer 1

Answer

DC Gain A_v =60dB

According formula

$A_{vdB}=20\log_{10}A_v\\60=20\log_{10}A_v\\A_v=1000$

Now gain in frequency form

$A_{v}(f)=\frac{1000}{\sqrt{1+(f/1000) ^2}}$

For frequency f=10Hz

$A_{v}(f)=\frac{1000}{\sqrt{1+(f/1000) ^2}}\\=\frac{1000}{\sqrt{1+(10/1000) ^2}}\\=999.95 \\=60dB$