Electronics, Example 5

 

Two-Stage Amplifier Analysis

Solve for the gain, plot frequency response.

Source

Schematic

colab optimized (share)

Can we be more accurate with cut-off freq? Yes, use transfer function.  (based on AIStudio)

Opus 4.6 extended. exact, transfer function, −3 dB crossing at 77 Hz, parameters as above original

Gain is 7943=78.0 dB considering Early voltage. 8511=78.6dB ignoring it.

exact transfer function vs. factored transfer function

bypass 47, coupling 10 micro F

(gain approximate)

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• Artifact, Share (Cπ2=15 pF, Cμ2=3pF). Result: freq response, gain=8513, low cut off=46.5 Hz, high cut off=312kHz
• Gemini: Result gain=8509, low cut off=46.5 Hz, high cut off=296 kHz @Cπ2=15 pF, Cμ2=3pF (good match!)

Compare

• Artifact, Share. Result: gain=8559 (Hybrid-π Model, With bypass capacitors, without ignoring base current loading effects)
• Artifact. Result: gain=9460 (Ignored base current loading effects)
• comprehensive comparison simplified, do not ignore bias network, do not ignore base current