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  1. hevans1944

    Artificial Intelligence

    I have been wondering how to approach this subject in an open forum. I am currently in a private conversation here on MakerPro with someone much younger than I am who is interested in AI research. As a (mostly) retired electrical engineer, I find it fascinating that folks are scared of AI. It is...
  2. hevans1944

    I am seeking a builder person/friend. I'm a project manager in my head.

    Please clarify what "a step-phase magnetic array" does, and what it means to you. A DuckDuckGo search revealed this link as the first result of the search. What does it have to do "toward a Star Trek tricorder?" We don't much like to play 20 questions here. I see that not only are you new to...
  3. hevans1944

    Trying to identify what these are

    The point of suggesting that you use AA cells was to allow you to try different voltages while minimizing noise pickup. An adjustable bench power supply is okay of course, unless you experience noise problems. Power supply switching noise can be a common problem for some applications that use a...
  4. hevans1944

    Trying to identify what these are

    Go to the link and look at the two schematics on the first page. The circuit on the left provides some amplification and uses a +9V DC supply. The circuit on the right performs an impedance transformation (from the high impedance of the electret to the low impedance of a 8.2 kΩ ohm resistor) and...
  5. hevans1944

    Speakers and Bass Frequencies

    Ima gonna jump in here and ask: what about cochlear implants? These are pretty crude right now, having something like ony 24 "channels" of audio spectrum... definitely not "high fidelity"...but with modern technology, this could be extended to hundreds or thousands of channels. The surgery...
  6. hevans1944

    help finding a micro controller

    @bobers: I forgot to mention that you MUST use either 60% Sn/40% Pb tin/lead alloy or a eutectic 63% Sn/37% Pb tin/lead alloy. NEVER use 50/50, sometimes called "Plumber's Solder" for electronic use. If your solder has a flux core, make sure it is a non-corrosive flux specified for electronics...
  7. hevans1944

    Trying to identify what these are

    You might want to look at the information at this link. Many electret microphones use a permanently polarized dielectric and will therefore produce an audio output using just two wires. However, the output impedance of a bare electret is very high, so (although the signal level is quite large)...
  8. hevans1944

    help finding a micro controller

    The T24-0 marking appears to be a date code. As long as the NDP1331KC part number is on your replacement component, it should work fine. Along the lines of @Bluejets recommendation, consider also using an inexpensive re-work/vacuum de-soldering station, including a pin-point vacuum "solder...
  9. hevans1944

    Capacitor type in low pass filter

    Awww! I LOVE them little ferret creatures. Had one living in our basement in Dayton, OH many years ago. It didn't make the trip to Florida when we moved here in December 2016. I like Angus cattle, too, cuz they tastes so gooood. We cooked up a pair of Angus filet migon steaks for dinner tonight...
  10. hevans1944

    Capacitor type in low pass filter

    Hey! Get wit da program. Not all them "audiophiles" have Golden Ears. Those that DO have Golden Ears will want to spend big bux for Oxygen Free High Conductivity (OFHC) speaker wire with gold-plated terminals on the ends. If they have really deep pockets, they will buy speaker wire made from...
  11. hevans1944

    LC oscillator and resonance frequency

    Nothing wrong with that. I had problems "visualizing" reactance, much less understanding it, when I was growing up. Grandfather got me started learning about DC electricity by describing Ohm's Law, but that wasn't enough to even begin to explain what happens when you try to force current (the...
  12. hevans1944

    LC oscillator and resonance frequency

    Mind-altering drugs, whether that be a single-malt Scotch whisky, or a fine bourbon aged in charred oak barrels, or perhaps a fine wine, or perhaps something prescribed by a medical doctor, for example medical marijuana, are some of the ways of coping with this fascinating world we get to...
  13. hevans1944

    LC oscillator and resonance frequency

    Lessee... you reject circuit analysis using algebra and well-known mathematical formulas that describe how capacitive and inductive reactance vary inversely with each other as a function of frequency. Then you postulate that when these reactances are equal (same modulus in your words) the...
  14. hevans1944

    Very high current power supply

    If you do a search on the phrase "FSAE electric vehicle" this web page appears at the top of the results. The yearly SAE EV "contest" began on June 14, 2023 (today, as I write this) and runs through June 17. I am guessing it is waaaay too late for further responses in this thread to be useful to...
  15. hevans1944

    Basic transistor switch

    Thanks for that link. The Microchip forum link reminded me that to effectively use a Microchip PIC, one has to closely read the entire datasheet. A designer using the PIC must know to what state power-on reset, as well as brown-out and other resets, each I/O pin defaults to and adjust their...
  16. hevans1944

    Basic transistor switch

    Finally! A thread that tells it like it is. @danadak's schematic shown in his post #5 is the most general implementation of a transistor, either bipolar junction transistor (BJT) or metal-oxide silicon field-effect transistor (MOSFET) or insulated-gate field-effect transistor (IGFET) used as a...
  17. hevans1944

    Ultrasonic trans/rec transducer support hardware

    I have been following this thread with some interest... years ago we did a lot of outdoor cooking on a propane gas-fired grill. The propane tanks were heavy when filled and a lot lighter when empty. The difference between "filled" weight and "empty" weight is easily measured with a bathroom...
  18. hevans1944

    Will get pulsating DC on a transformer's secondary if I apply pulsating DC to it's primary?

    I sincerely hope this isn't another HHO electrolysis attempt to get "free" energy to operate an automobile internal combustion engine using just water, an alternator to generate electrolysis, and hand-waving explanations... hmmm. To better get electrolysis, pure water needs an assist, a catalyst...
  19. hevans1944

    The T-Board keyboard. And my first PCB! (Designed with OsmondPCB.)

    It's Jew's Harp NOT Jewish harp. The name, however popular, has NOTHING to do with Jews or religion. Here is a YouTube video of one guy demonstrating how to to play it. It looks like an expensive toy when built with state-of-the-art (SOTA) technology. The source and trace of the original harps...
  20. hevans1944

    The T-Board keyboard. And my first PCB! (Designed with OsmondPCB.)

    Hmmm. It might have been that I didn't turn on my JBL Charge 4 external speakers. I just now tried playing the video again and the sound is there as long as I have the JBL speakers powered up. My bad. The video quality is also good. Fourteen megabytes is a small file these days, but I understand...
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