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  1. WHONOES

    Questions regarding voltage divider for micro controller sensing

    As I said in post 2, you need to determine the input impedance of your device as it will be in parallel with R2 and will affect the result.
  2. WHONOES

    Comedy Thread

    A thought or two For something to be extreme, it must have been tremed at some point. To expire, you must have pired at some time. To expect must you have been pect? There is loads more out there. Suggestions.
  3. WHONOES

    Silent electric motor to drive turntable.

    The following link might help to identify ways of reducing gear noise. How much noise is too much. What is the purpose of your device. It takes surprisingly little power to rotate a mass at a relatively low speed.
  4. WHONOES

    Comedy Thread

    Is Donald Duck Transgender? Surely it should be Donald Drake??
  5. WHONOES

    Problem with farward converter

    From the little I can glean from you faint diagram, it looks like you are using a push - pull drive. One of the problems with this topology is that you can have a problem called "Shoot Through". This arises from both the output devices being very briefly on at the same time causing a large...
  6. WHONOES

    Questions regarding voltage divider for micro controller sensing

    The sum you need to derive the correct division ratio is (V1 / V2) - 1. You also need to take into account the loading effect of the attiny85's input impedance as this will shunt R2 resulting in an error. If you can determine its impedance, you could adjust the value of R2 to compensate. Using...
  7. WHONOES

    Sensing AC voltages

    Look at the following link for a DMM that measures voltage without physical contact. Not very expensive either.
  8. WHONOES

    Capacitor Substitution

    RT1 may be the current sense resistor which would make sense if you found that it had a dry joint and all is now working OK since you rectified it. Well done, glad you have got it sorted.
  9. WHONOES

    current limiting to 2A Input 60V

    What does the rest of the circuit consist of. More info please.
  10. WHONOES

    Capacitor Substitution

    Can you provide close up photo's (as close as you can whilst still in focus) on both sides of the board around the burnt area?
  11. WHONOES

    AC Polarity swapping circuit

    Tell us what you are trying to do with this project otherwise we are likely to give up as we are just taking shots in the dark
  12. WHONOES

    Capacitor Substitution

    Sounds like you have a problem with a current limiting circuit cutting in to early. This could be due to a sense resistor getting a bit frazzled and its resistance increasing a bit or it might be the active element be it transistor or IC having a problem. I would check for a low value resistor...
  13. WHONOES

    Amp repair

    Have to agree with you BJ.
  14. WHONOES

    AC Polarity swapping circuit

    I would say that's it's a lot of f*rting about for the sake of a few A$. The link I provided shows a completed board for A$12.5, hardly a Kings Ransom.
  15. WHONOES

    Lets take a look at a linear amplifier

    For your transformer, look at the following link. As for the suitability of the TI solution, only you can decide that. https://www.electronics-tutorials.ws/transformer/transformer-basics.html
  16. WHONOES

    AC Polarity swapping circuit

    Have a look at the link below. https://www.banggood.com/HiFi-LM3886-TF-Mono-68W-4-Audio-Power-Amplifier-Board-AMP-50W38W-8-p-1190627.html?rmmds=buy&cur_warehouse=CN Edit: Yes you will need an oscillator to generate the required waveforms or, as suggested earlier you could use a pic or...
  17. WHONOES

    Lets take a look at a linear amplifier

    Have a look at a thread on the following "TI" link that seems to do something similar to your requirements. https://e2e.ti.com/support/audio/f/6/t/483271
  18. WHONOES

    Amp repair

    The standard of soldering in your picture looks horrible. I assume you haven't been messing around with a soldering iron. Also, there seems to be an awful lot of cr*p on the board which won't help. Could be a cart load of dry joints and shorts from rubbish floating around.
  19. WHONOES

    Lets take a look at a linear amplifier

    Looking at you amplifier schematic, it is overly complicated. Much simpler solutions are available. Also, if you plan to use + and - 90V as indicated on your diagram, the TIP142 and 147 combination will not be suitable as they are only rated to 100V.
  20. WHONOES

    AC Polarity swapping circuit

    In your first post, you say that you want to drive 32vac at up to 30Watts. That is well within the capability of a power amplifier. You could then use a pic or some other type of processor to construct the wave form and sequence you require to drive the amplifier.
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