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  1. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    The turns ratio of the transformer determines its output voltage. Then you will need heavier wire for everything and an extra pair of Mosfets for the higher power.
  2. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    The inverters in high power car amplifiers operate at about 65kHz and use Mosfets. Then the transformer and filter caps can be tiny. http://www.sound.westhost.com/project89.htm
  3. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    If you tune a winding on a transformer with a capacitor and drive it with a high impedance so the Q remains high, then the output would be a perfect sine-wave without a load and the voltage would be infinite, then turn into a square-wave at the normal voltage when a load is added.
  4. audioguru2

    Another INVERTER we can talk about..

    ELFA will replace it only within one year. I have a garden hose that has an unlimited warranty. It gets weakened by the sun and fails every two years and I get it replaced over and over.
  5. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    With a low output voltage at 3A, the output transistors must dissipate 121.5W. With 5A then they must dissipate 202.5W. A single 2N3055 transistor can dissipate 115W and it's chip will be at its absolute max temp of 200 degrees C if you somehow keep its case at 25 degrees C. The thermal...
  6. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    Be careful you don't go deaf. Many speakers have a sensitivity of 90dB/1W/1m. 250W in them produces a sound level of a whopping 114dB at a distance of 1m and 117dB if two speakers are playing. Much too loud.
  7. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    I don't know how good is the sine-wave from a ferroresonant transformer that operates saturated and has a square-wave input. Since its primary is saturated then I don't know how high is its input current. A ferroresonant transformer is rare so probably is very expensive.
  8. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    That is an awful lot of power. What is it for?
  9. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    I don't know what is the airflow amount of your fan and how much airflow your heatsink needs to blow out the fire. Try it.
  10. audioguru2

    Another INVERTER we can talk about..

    Hi Ante, The sine-wave inverter is made in Taiwan by "nobody" but I suppose that ELFA will replace it if it fails. It might be good.
  11. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    It is nice but the heatsink is too small for this project. The 30VAC transformer has a peak voltage of 42V which is reduced to about 40.5VDC by the bridge rectifier. If the output is a low voltage or is shorted and the current is set to 3A then the output transistors will dissipate 40.5V x 3A=...
  12. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    Are your speakers 4 ohms? The amplifier makes 250W into 4 ohms or 144W (maybe 150W) into 8 ohms per channel. I don't know if it can have 2 channels bridged to make 500W into 8 ohms.
  13. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    It has a square-wave output so its peak voltage is too low to operate many electronic devices whose rectifier charges its main filter capacitor to the peak voltage of a sine-wave from the mains. It is smart enough to use Mosfets for reduced heating instead of the hot ordinary transistors in our...
  14. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    You have a nice big heatsink, but you will be surprised at the amount of heat that your linear sine-wave inverter will make and a fan is probably also needed.
  15. audioguru2

    Another INVERTER we can talk about..

    I have an MM5389 IC with a 3.58MHz color TV crystal making 60Hz. The IC is very old and has not been made for many years. It is so old that I couldn't find its datasheet to see if it can also make 50Hz.
  16. audioguru2

    Another INVERTER we can talk about..

    The calculation for the frequency of a CD4047 oscillator is shown in its datasheet. It is used as a 50Hz or 60Hz oscillator in our 500W inverter project and here is the corrected schematic of its oscillator. What is an MM5389??
  17. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    I don't know about any books. Make a very hot linear output stage, a cool but complicated PWM output stage or use an expensive ferroresonant transformer at the output of a square-wave output stage.
  18. audioguru2

    Simple & sensitive room bug for newbies!

  19. audioguru2

    0-30 Vdc Stabilized Power Supply

    Good point! ;D Without a filter then maybe the current regulation is noisy.
  20. audioguru2

    Stereo Audio power amplifier 2 x 40W - 80W

    Amplifier outputs should not be paralleled without adding series resistors. The resistors will waste power and cause poor voltage regulation. Eight 12V batteries in series can power many amplifiers. But then the charge in the batteries won't last very long.
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