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  1. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Maksar, That's a nice heatsink, but I don't think it is made to fit TO3 cased transistors like 2N3055's. It has a space of only 27mm, and with tolerance might be slightly less. The max width of a 2N3055 is 26.67mm so it would make an extremely tight fit. I don't know if the machined surface...
  2. audioguru2

    0-30 Vdc Stabilized Power Supply

    Only if you use a heatsink with an infinite size, with a high velocity fan blowing on it. Also, only if both your 2N3055 transistors have more gain than their guaranteed minimum. Also, Only if you don't operate the power supply project at a high output current at a low voltage output. Otherwise...
  3. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Tedy, A little old 2N2219 in a heatsink can dissipate only a couple of watts and will be at its absolute max temp. A TIP31 can dissipate 20W to 40W. If your project is set for a low output voltage and a high current, you are going to melt the little 2N2219! ;D
  4. audioguru2

    frequency to voltage converter

    Hi Mark, The AGC circuit of a TV controls its gain (Automatic Gain Control). It is well-filtered so that it doesn't have any AC signal which would modulate the picture. Therefore it doesn't have a frequency, just a DC voltage that varies with RF signal strength. What is your microcontroller...
  5. audioguru2

    scalar beamer

    Hi Steven, If that thingy puts you in a trance, I hope you have some method to come out of the trance. You might end-up being a zombie. :o Be careful with weird things like that!
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

  7. audioguru2

    0-30 Vdc Stabilized Power Supply

  8. audioguru2

    need a help

    Simply use Ohm's Law: The resistance equals the voltage divided by the current. The resistance is a current-to-voltage converter. Just feed a known amount of current into a resistance and the voltage drop across it will be determined by its resistance. You could also put a known voltage across...
  9. audioguru2

    Beginning Projects

    LEDs are a diode almost like any other diode and have a fixed voltage drop that varies with each one and its colour. Since the voltage drop is fixed, you must connect a current-limiting resistor in series with each one which sets its current. If you connect LEDs in parallel then the one with the...
  10. audioguru2

    FM Radio

    An inductor that you purchase is a coil of wire, almost like the one you can make. It is wrapped in plastic , tape or something so it can't be adjusted and its value is in color bands on it. A microwave inductor is a stripline, or piece of straight wire or rod and its inductance is determined...
  11. audioguru2

    FM Radio

    Hi Ahmed, Welcome to our forum. ;D The IC hasn't been made for years. Where did you get one? The coil is simple to make, if you buy one then you won't be able to adjust it. Just make it and adjust it like explained above.
  12. audioguru2

    What is a piezo 82dB

    Hi Walid, An 8 ohm 0.25W speaker and the transistors will blow up in that circuit. An ordinary speaker won't reproduce very high frequencies anyway. Motorola's piezo tweeter was used in many cheap big speakers for guitars and stuff. Search for Motorola Piezo Tweeter in Google for places selling...
  13. audioguru2

    Advice on Equivalent transistors

    Experience. ;D
  14. audioguru2

    the great differences btw 555 and 4060

    A CD4541 timer IC is like a CD4060 in that it has an oscillator and digital counter. But it works better than a CD4060 as a timer because it has automatic power-on reset, has a built-in mono-stable and your choice of output polarity. ;D
  15. audioguru2

    What is a piezo 82dB

    Hi Alun, An 8 ohm tweeter will be about 25 ohms at 30kHz. I don't know the capacitance of a piezo but I don't think it is as low as only 25 ohms (0.2uF). ;D
  16. audioguru2

    Need advice on equivalent transistors of: SL100 and BC158A

    Just about any little transistor will work in that simple circuit. I would use a 2N3906 to replace the BC158A, and a 2N3904 to replace the SL100. The American transistors have a reversed pins layout from the Euopean transistors. ;D
  17. audioguru2

    What is a piezo 82dB

    Hi Walid, A piezo transducer can operate at very high frequencies and has a high impedance. Many speakers don't work at very high frequencies and are a low impedance. Post the schematic of the pest repeller circuit so we can see if its output transistors will melt when trying to deliver a high...
  18. audioguru2

    Transformer Power Rating

    Hi Crflorin, Welcome to our forum. ;D I think your amp experienced "thermal runaway", where the transistors heated causing them to conduct more, causing more heating which caused them to conduct even more, causing even more heating etc. The project says, "The transistor Q7 is used to balance...
  19. audioguru2

    Infrared Activated Switch

    HEHE, silly you again! ;D Tip: You got it wrong, try this:
  20. audioguru2

    Infrared Activated Switch

    It looks like we are using the pin numbers of a single TL071 opamp instead of a dual opamp. Check the datasheet for the correct pins. :o
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