# Voltage gain in low-mid frequency range

Discussion in 'Homework Help' started by yoamocuy, Jan 22, 2011.

1. ### yoamocuy Thread Starter Active Member

Oct 7, 2009
84
0
Find and sketch voltage gain in the low-mid frequency range. Compute maximum gain and cutoff frequency (rad/sec). A picture is attached.

We just started doing this in class and haven't had any lectures over it yet. I've read our book a bit but am still a bit lost. Isn't the gain shown in the picture going to be the maximum gain? I believe that the gain in the low-mid frequency range is going to be -Amax*(s/(s+ωp1))*(s/(s+ωp2))*(s/(s+ωp3)), but I'm not sure how to find those values with the circuit in the form that it's in. If I had the values of Cc2 and Ce I feel like I could calculate everything, but since I only have Cc1 I'm not sure what to do... I could be completely off track, I'm not sure.

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2. ### Audioguru Expert

Dec 20, 2007
11,251
1,350
The source resistance of 600 ohms plus the amplifier's input resistance of 100 ohms is what the 6uF input capacitor drives. So 38Hz (the cutoff frequency) has a gain of 70.7 times and frequencies above 380Hz have a gain of 100.

The sketch is just a slope of -6dB/octave below 38Hz and a flat line above 380Hz.

There is no Cc2 nor Ce shown.

3. ### yoamocuy Thread Starter Active Member

Oct 7, 2009
84
0
Ok, thanks. That helps a lot