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transistor amplifier

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mstechca

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Now that I got my FM radio working OK, I want to be able to amplify the sound (by making an amplifier portion and adding it to my existing output) so that I can hear my radio from at least two meters away.

I want to make the amplifier portion of the circuit using only BJT transistors. I want to limit the use of capacitors as much as possible. I am using a 5V power supply.

Or, I want it where I can at least get an LED to correspond to the output. (so its like making lights dance to the music).
 

hamfiles

New Member
try:

http://www.techlib.com/electronics/audioamps.html

The second ciruit listed uses 4 transistors in class AB configuration, w/ supply voltage of 4.5 to 5 volts. You might want to replace the 1 k resistor (the one that feeds the first diode) with a variable resistor of about 0 -2 k , and adjust it for about 2.5 volts at the output, before the 220 microfarad cap, and do this with no input load.

Before you do this, check the voltage w/ 1k resistor, and see if it is already biased properly.
 
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