Hello,
I am designing an audio amplifier using BJT's and I was hoping for some advice before I buy components and put it on a board. My requirements are as follows:
Voltage Gain: Av = 50;
Input Impedance > 70 KΩ
Output Impedance < 8Ω
Available power supplies are voltage regulated +12V and –12V.
fL=20Hz fH=20KHz
Maximum Symmetrical Swing = At least +/- 1.2V
My design uses +-15V rails, this is ok.
Attached are my Multisim simulation that gives me a gain of about 52. (v-probe2/v-probe1)
My input impedance matches R1 for most frequencies between 20 - 20k. I calculated this with (v-probe1/i-probe1) - Is this a valid way to calculate the input impedance?
I measured output impedance the same way (v-probe2/i-probe2) - It looks good right around 8 ohms.
The frequency response is off, (picture attached) - I get no cutoff. Id rather not build filters as I hear that is a good way to such power out of the amp, but my limited knowledge pushes me in that direction.
Other than that I used generic transistors for the circuit - I was planning on putting power BJT's on the output stage.
Any ideas help or suggestions would be greatly appreciated.
Thanks.
I am designing an audio amplifier using BJT's and I was hoping for some advice before I buy components and put it on a board. My requirements are as follows:
Voltage Gain: Av = 50;
Input Impedance > 70 KΩ
Output Impedance < 8Ω
Available power supplies are voltage regulated +12V and –12V.
fL=20Hz fH=20KHz
Maximum Symmetrical Swing = At least +/- 1.2V
My design uses +-15V rails, this is ok.
Attached are my Multisim simulation that gives me a gain of about 52. (v-probe2/v-probe1)
My input impedance matches R1 for most frequencies between 20 - 20k. I calculated this with (v-probe1/i-probe1) - Is this a valid way to calculate the input impedance?
I measured output impedance the same way (v-probe2/i-probe2) - It looks good right around 8 ohms.
The frequency response is off, (picture attached) - I get no cutoff. Id rather not build filters as I hear that is a good way to such power out of the amp, but my limited knowledge pushes me in that direction.
Other than that I used generic transistors for the circuit - I was planning on putting power BJT's on the output stage.
Any ideas help or suggestions would be greatly appreciated.
Thanks.
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