help me with homework

Thread Starter


Joined Nov 8, 2011
Please can someone help me on this problem. I need to know where to start, I know I need to use a MOSFET​

Design, build and test an AC coupled amplifier powered from a 12V supply with the
following specification.​

Input voltage: 100mV

Covers the audio frequency range: at most 50Hz to at least 10kHz

Gain: 24±2 dB (gain should be flat over the specified frequency range)

Output should not be inverted

Input impedance: >1.2 MW
· Output impedance: <180 W
· No resistors <220 Ohms to be used​
· No parallel resistors on transistor output stages


Joined Nov 25, 2009
Greetings! And welcome to AAC!

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Thank you.


Joined Feb 12, 2009
I was going to suggest a "common source" amplifier (which you could Google). But this will give an inverted output.

If you want voltage gain, high input impedance, low output impedance and non-inverting you will need more than one transistor.

You could use two common source amplifier stages, the first one feeding the second one. Each one inverts, therefore the complete circuit does not. To accurately control the gain you need to use overall negative feedback.

Have you been given any more clues in your course notes?