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Recent content by audiomik

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    Transistor direct replacements: 2N3440 and 2N5415

    Thanks for the replies, did think that there isn't a direct replacement after looking hard so thought asking on here could be useful Mik
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    Transistor direct replacements: 2N3440 and 2N5415

    E-design thanks, but I certainly wouldn't trust your equivalents book! All of the BCxxx suggestions on lookup are far too low voltage, current and power rating! The 2N3440 and 2N5415 are complimentary 250V types and 1 Amp max devices, and I cant find the BFT types or the MJ one in supplier...
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    Transistor direct replacements: 2N3440 and 2N5415

    Am trying to find direct replacements for the 2N3440 and 2N5415 TO39 cased transistors to use in an update of an old design. Both of these are now appearing as 'obsolete' from suppliers and Ebay isn't an option! Either TO39 or Plastic cased flat-pack types will be suitable as a new PCB is being...
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    Sensitive microphone

    For your application, have a look at the AD 637 IC from Analog.com which will convert your microphone pre-amplifier output signal directly into a 60dB range display. Full information on how to do this is within the datasheet...
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    [SOLVED] Sine Wave Inverter - noisy output (LF) transformer

    check for a lose lamination in the transformer core? Mik
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    Calculating current draw of Class A amp

    Picking up on betwixt's point on Loudspeaker Impedances, a minimum Impedance for the Loudspeaker you might use can be easily assessed by measuring the DC Coil resistance. This will be very close to the minimum Impedance which will be much more useful when trying to assess Power requirements...
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    Very low frequency crystal oscillator

    Luben you might look at having two Crystal oscillators and using the difference signal. This will at least enable the use of readily available higher crystal frequencies for your project. Perhaps look at a tuned LC circuit at the output of the summed signal with a suitable secondary to achieve...
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    Home made audio amplifier powered by running PC PSU?

    Re: "My gut feel says 100uF should be fine but 10000uF may be a problem. However I've never tried it, so some experimenting would probably be a good idea." Suggest also parallel connecting a 10 to 100nF Disc Ceramic onto the electrolytics as there are some high frequency switching 'spikes' on...
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    Problem with KiCad on windows7 SP1 ultimate

    Check the md5sum of the file(s) you have downloaded and installed to confirm that you have no corruption. If this returns an error, download, check and install again. Otherwise, you might find your problem listed here? https://bugs.launchpad.net/kicad Mik
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    my power amp not work how to fix it?

    jengsyber from experience of having built a number of 3 Phase versions of what you are trying to achieve, the solution is to have a bridge mode Amplifier circuit capable of driving very low load impedances. This then is used to drive a suitable transformer to achieve your desired output. A...
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    24V/15A simple power supply

    As a 'rule of thumb' main reservoir capacitors should be at least 1000µF per Ampere of output current. Thread title is for a 15A supply, so a suitable value could be 22,000µF at 40 Volts working whilst ensuring that the component has a suitable ripple current rating, in this case for 100Hz. Mik
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    24V/15A simple power supply

    Bridge Rectifier: same or similar to this: https://uk.rs-online.com/web/p/bridge-rectifiers/2278744/ will be a good choice. Bolt it directly to the metal chassis you use to build your PSU onto. Calculate your Transformer VA Rating from the previously attached link..... add a bit more (next size...
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    24V/15A simple power supply

    A few things which you need to look at: The VA Rating of your Transformer Current Rating of your Rectifier Ripple Current for your Capicitor (C1) Otherwise your general circuit will work. All of these are covered in this useful paper: **broken link removed** hope this helps Mik
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    hall effect current sensor for measuring ac current

    Can you post a link to an English datasheet and application notes for the wcs1600? All I seem to be able to find are in Chinese(?) Mik
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    Measuring output Wattage, power amp only VS preamp + power amp

    Find the zero volts connection on the main smoothing capacitor in the Power Supply. Temporarily solder a piece of single insulated wire to this point, long enough to reach to where your input and Pre-Amplifier output connectors are, and use it for your 'Scope ground clip. Don't forget to remove...

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