Does any Know how to design simple Stereo Audio Amplifier(Pre-Amp+Tone Control+Output Stage) by using LM358 op-amp and (8 ohm Speaker) ,the circuit should be working with 4.5V (e.g. 3 AA batteries)...????
I designed several circuits but I got 2 much noise
I really need some help PLZ....one of the circuit that I built is show below(Op-Amp Audio Amplifier)...
I designed several circuits but I got 2 much noise
I really need some help PLZ....one of the circuit that I built is show below(Op-Amp Audio Amplifier)...
An externally hosted image should be here but it was not working when we last tested it.
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Two problems: too much voltage gain (x300), and a noisy signal reference due to thermal noise from the 1M resistors. Assuming a 20kHz bandwidth I calculate 5.4mV of noise at the output, which is likely to be audible.
Another possible issue is instability. RF oscillation sometimes shows itself as excessive audio noise.
Another possible issue is instability. RF oscillation sometimes shows itself as excessive audio noise.
I'm experimenting this circuit but unfortunately,i'm still facing these problems.... any suggestion with some details to how reduce excessive audio noise....any help, I will appreciate it..
http://www.diyaudio.com/forums/attachments/construction-tips/248851d1321036112-design-simple-stereo-audio-amplifier-stereo-audio-amplifier-circuit.jpg
http://www.diyaudio.com/forums/attachments/construction-tips/248851d1321036112-design-simple-stereo-audio-amplifier-stereo-audio-amplifier-circuit.jpg
All resistors carry <a href="http://www.physics.ucdavis.edu/xdzhu/Physics122_2008/Johnson%20Noise%20Manual_2008.pdf">Johnson noise</a>. The higher the R value, the greater the noise. Your 1M resistors seem to be way high for normal outputs. You might also check the National Semiconductor <a href="http://www.national.com/ds/LM/LM158.pdf">datasheet</a> for your opamp for some ideas.
why?I can not use any LED driver chip like LM3916 or LM3915....just transistors and LEDs
Could this be another case of non declaration of student/pupil status?
Because for my experiment there are specifications for using some components,the list of the component that I can use to design the volume meter circuit : Transistors, Resistors,LEDs,Capacitors and AA batteries>4.5 volts.
So if any one can help me and provide schematic diagram I will appreciated..
Many thanks....
So if any one can help me and provide schematic diagram I will appreciated..
Many thanks....
I got this schematic diagram but I'm not pretty sure what is wrong with it!!!!Please feel free to comment on it...
regards..
regards..
An externally hosted image should be here but it was not working when we last tested it.
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