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  1. #1
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    Amplifier with 50khz frequency and 1 A output

    I made an amplifier with input from function generator(3V,sine wave,frequency upto 50khz). When i try to get output for 1khz frequency,i get around 1A but when i go for higher frequency like above 5khz,it doesn't work and gives around 200mA. Even the dc power supply to transistor can't be reached above 6 V. I tried giving above 6V dc but the supply won't let me for higher frequency. Can someone please tell me why am i facing such problem.I am attaching the datasheets of the transistor.

    Click image for larger version. 

Name:	audamp.png 
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ID:	154321

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  2. #2
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    Re: Amplifier with 50khz frequency and 1 A output

    Is this a real circuit or simulation? What do you mean “dc power supply to transistor can’t be reached above 6v”? Do you mean your 10V supply only puts out 6 volts?



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  3. #3
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    Re: Amplifier with 50khz frequency and 1 A output

    Maybe your multimeter cannot accurately measure currents above 1kHz? Maybe your power supply cannot provide enough power for all the heating?

    You call your schematic "audamp" but audio amplifiers have not used antique TIP3055 and TIP2955 transistors for about 40 years.
    It seems that the simple biasing with very low value resistors overloads your function generator and the transistors are overloading their power supply since both transistors are both turned on all the time, with more and more current as they overheat.
    Look on the web for modern high power amplifier circuits and you will see that their newer output transistors are driven with driver transistors and have the biasing thermally stabilized with diodes or a transistor attached to the heatsink.
    Audio amplifiers today produce full output up to at least 30kHz. They use negative feedback for higher bandwidth and lower distortion.



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  4. #4
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    Re: Amplifier with 50khz frequency and 1 A output

    Quote Originally Posted by rhonny View Post
    I made an amplifier with input from function generator(3V,sine wave,frequency upto 50khz). When i try to get output for 1khz frequency,i get around 1A but when i go for higher frequency like above 5khz,it doesn't work and gives around 200mA. Even the dc power supply to transistor can't be reached above 6 V. I tried giving above 6V dc but the supply won't let me for higher frequency. Can someone please tell me why am i facing such problem.I am attaching the datasheets of the transistor.

    Click image for larger version. 

Name:	audamp.png 
Views:	24 
Size:	22.0 KB 
ID:	154321
    This is a terrible circuit design. Please change it based on some proper knowledge, and THEN if you have problems you can come back here. Otherwise it is waste of time for everyone.



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