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Type: Posts; User: Audioguru

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  1. Closed: 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...
  2. Closed: Re: HELP with Schematics for magnet launcher

    On the other websites you said you know nothing about electronics.
    The video has no part numbers so how do you know if you have suitable parts? Your parts might blow up and injure you or cause your...
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    [SOLVED]Closed: Re: whats hfe during peak current

    The maximum allowed collector current of an old 2N3055 transistor is 15A. They guarantee that it saturates not too bad with a collector current of 4A when its base current is 400mA (1/10th). They...
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    [SOLVED]Closed: Re: Different ways of presenting a circuit

    Didn't your teacher teach you? The AND gate is simple:
    1) If both A and B inputs are not connected to anything or are both a logic high, then the diodes do not conduct so the resistor to the power...
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    [SOLVED]Closed: Re: whats hfe during peak current

    The graphs on a datasheet show only "typical" devices. The text in the datasheet says the guaranteed minimum and maximum values.
    The package for a device does not affect the hFE, it affects only the...
  6. Closed: Re: Adding a light parallel to existing loudspeaker circuit

    On the other two websites he was told that an old fashioned incandescent light bulb is like a dead short circuit when cold and it would destroy the amplifier.
    Of course the speakers are not...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    It could be worse if the TIP41 and TIP42 transistors have their minimum hFE and the supply is a normal 13.2V battery:
    1) If the output power wanted is only 13.2W then the transistors conduct 1A....
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    Closed: Re: tda2030 amplifies noise

    The non-inverting input level of your TDA2030 amplifier depends on its output level divided by your gain of 1 + (100k/4.7k)= 22.3 times. but since you are using the minimum supply of 12V the...
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    Closed: Re: tda2030 amplifies noise

    If the preamp creates the hiss then of course if you add a lowpass filter to its output then you cut the hiss and all other audio high frequencies.

    Here we go again. I downloaded the datasheet of...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    ebay is Chinese and sells cheap fake or defective Chinese electronic parts.
    AliExpress is also Chinese and sells cheap Chinese parts. Fakes? Made by Chinese companies I never heard of.

    ON Semi is...
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    Closed: Re: tda2030 amplifies noise

    Many cheap amplifiers and speakers have the volume turned WAY UP so that the amplifier is clipping like crazy producing lots of awful distortion to make the power output number higher. Then they...
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    Closed: Re: tda2030 amplifies noise

    I have never seen a TDA2030 or TDA2030A. I deleted the datasheet of the old TDA2030 but you can look it up to see if it spec's noise level like the TDA2030A datasheet does. The noise level spec'd for...
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    Closed: Re: NE555 astable frquency

    That circuit is all over the internet.
    Hey Google: 555 oscillator circuit with duty-cycle adjustment
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    Closed: Re: tda2030 amplifies noise

    The TDA2030 is old and was cheap so of course it produces hiss. It is not made or available anymore. The more modern TDA2030A also is obsolete and is not made or available anymore.
    An LM3886 is more...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    The old inverter circuit in this thread was designed long before Cmos 555 ICs were even dreamed about.

    My electricity is very reliable so I have never bought or made an inverter. On the few rare...
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    Closed: Re: Noise in My Audio Amplifier

    Please describe the noise: Low frequency hum? High frequency hiss? A continuous tone? A pulsing tone?
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    OK, I agree that this squarewave inverter uses emitter-followers and not saturated switches. The original TIP41 and TIP42 transistors have a minimum current gain of 12 at 5A but the transistors you...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    The gain of output transistors is needed in a linear amplifier. But this circuit is not a linear amplifier, its transistors are saturated on-off switches.
    The (Japanese?) transistors recommended...
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    Closed: Re: 9V rechargeable battery circuit

    The schematic was missing the AC input voltage, the battery type (Lithium-Ion), how many cells the battery has (so we know its maximum charging voltage) and now it is missing the mAh rating so we...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    That old circuit is begging for Mosfets instead of ordinary low gain transistors.
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    Is the NE555 a fake from ebay?
    Did you measure the resistance of the 100 ohms resistor? If it is shorted (ebay?) then the 555 gets hot when the circuit has a load.
    If the transistors are fake...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    It is impossible for an NE555 to get hot in that circuit since it is driving only 100mA into a 100 ohms resistor. Then why do you need a heatsink and fan? Why add another transistor? Fix the problem...
  23. Closed: Re: UA78M33CDCY 3,3 volt regulator will not regulate at input voltage above 12 vol

    Good. AliExpress sells cheap Chinese junk.
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    How can the timer IC get hot when its output feeds fairly low current into the 100 ohms resistor, not into the load?
    The 555 would get hot if its output is shorted, but instead it feeds a 100 ohms...
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    [SOLVED]Closed: Re: Tip41c/42c arrangement problem

    What is the part number of the 555? If it is from China then it is probably a fake.

    Maybe you connected the polarity of the battery backwards?
    Even if you connected the transistors completely...
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