I started out designing a multistage CE amplifier for small signals just to learn how to design these stages with proper biasing as well as impedance matching.
Here is the first part of this experimental design.
When I got that to work properly, I began working on a Class AB power amp, using the available supply of 8v.
I chose 8V. so I can use a 9V. battery to run this circuit.
Transistors Q3 and Q4 below schematic, are designed only to increase Zin to the push pull pair.
Here is the power amp.
Then I combined both circuits together to form the completed small sig. amp.
I tried to use emitter bypass caps. only where neccessary, and no feedback cap. that would hinder high freq. response, without C1 in the circuit the Av. ~= 20 due to signal in being small so as to not overdrive the amp.
Even at this small gain I tested the amp, by putting it through an actual sound test, I placed the input speaker ontop of the speaker of my portable DVD player and turned the volume down and listened and had excellent sound quality.
Then I added the Cap. C1 and feedback R1.
And heard everything very clear and louder also I was avle to pick up all the data handling sounds in my laptop computer, as well as the sounds off the LCD screen the sounds inside my DVD player ect..., to make sure it wasn't oscillations, internal in my circuit I placed the speaker away from everything and heard silence using a 9 volt battery.
This is my experimental first try in designing in a more systematic way trying to keep impedances matched as much as possible as well as not going overboard with base collector feedback capacitors.
here is the final circuit.
The one at the bottom is just a reapeatr I couldn't delete.
Here is the first part of this experimental design.
When I got that to work properly, I began working on a Class AB power amp, using the available supply of 8v.
I chose 8V. so I can use a 9V. battery to run this circuit.
Transistors Q3 and Q4 below schematic, are designed only to increase Zin to the push pull pair.
Here is the power amp.
Then I combined both circuits together to form the completed small sig. amp.
I tried to use emitter bypass caps. only where neccessary, and no feedback cap. that would hinder high freq. response, without C1 in the circuit the Av. ~= 20 due to signal in being small so as to not overdrive the amp.
Even at this small gain I tested the amp, by putting it through an actual sound test, I placed the input speaker ontop of the speaker of my portable DVD player and turned the volume down and listened and had excellent sound quality.
Then I added the Cap. C1 and feedback R1.
And heard everything very clear and louder also I was avle to pick up all the data handling sounds in my laptop computer, as well as the sounds off the LCD screen the sounds inside my DVD player ect..., to make sure it wasn't oscillations, internal in my circuit I placed the speaker away from everything and heard silence using a 9 volt battery.
This is my experimental first try in designing in a more systematic way trying to keep impedances matched as much as possible as well as not going overboard with base collector feedback capacitors.
here is the final circuit.
The one at the bottom is just a reapeatr I couldn't delete.
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