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  1. hevans1944

    LED for electric heater (UK)

    Yes, you can. If you order it with a 230 V rating you can put it across the incoming 240 V mains. The description on the PDF page says "Multi-chip LED technology" whatever that means and the column with specifications says it draws 20 mA. Whatever other components are inside the lamp housing...
  2. hevans1944

    What is this resistor? Help

    It looks like a metal-film or a carbon-film resistor. I doubt whether it is capable of more than one watt of power dissipation without forced-air cooling. Measure the voltage drop across it and verify the resistance is still 100Ω and then calculate how much power it dissipates: P = E²/R
  3. hevans1944

    Modular Controller build with Arduino (Teensy 3.5)

    You have more or less described HOW you want to DO something, i.e., proposed a solution, but I don't see anything that describes WHAT you want to DO. There may be other, maybe simpler, solutions. So... what is the purpose of all those buttons, of unknown number, that the "controller" connects...
  4. hevans1944

    Reading a ruler help, 1.2 or 1.02

    Yeah, I have trouble even seeing those itsy bitsy teeny weeny marks on a steel scale that is marked off in 1/64" increments. And it seemingly gets worse when that inch scale is only divided into fifty linear increments instead of sixty-four. I usually keep a set of vernier calipers with a dial...
  5. hevans1944

    Reading a ruler help, 1.2 or 1.02

    o_O
  6. hevans1944

    Electronics for prop control

    That would be my option, too, if given any say in the matter. It's a pretty simple procedure: slice open the skin over the cavity containing the device, disconnect the leads to the heart, remove the old device and re-connect the leads, test to make sure the new device is working with the...
  7. hevans1944

    Electronics for prop control

    Thanks, Ian, for the advice on sending them an invoice. That's clearly necessary, even if I don't expect them to pay it. My mistake was not getting a purchase order that specified exactly what was to be accomplished, the cost billable to UES, and the proposed delivery date. So far, the cost in...
  8. hevans1944

    3V battery circuit / back lit rocker switches

    Can you provide a wee bit more information about the rocker switch... like who makes it, what the model number or part number is, where you procured it, maybe a picture of what it looks like and a wiring diagram of the terminal arrangement? The contact current and voltage specifications have...
  9. hevans1944

    Electronics for prop control

    Thank you all for the supportive comments. And thanks for moving my off-topic comments to a new thread. I apologize for inflicting on you an update on my health problems. The move to Florida was more stressful than I had anticipated, but ultimately was in the best interest of my health... well...
  10. hevans1944

    Info for 2N3904 and 2N3906

    This is the only true statement in this comment. Everything after PNP ... to the final period at the end, including most of the "information" in the two links is either wrong, misleading, or irrelevant. In this forum, misinformed opinions can do great harm to the understanding of basic...
  11. hevans1944

    Electronics for prop control

    Last year, for the first time in my life, I signed a non-compete agreement with a re-seller of magic props used by the amateur as well as the professional performing magician. These are rather expensive props imbued with modern technology. In return, I was made privy to several magic "gimmicks"...
  12. hevans1944

    OrCAD PCB Designer PSpice

    You need to create a custom PCB footprint for those transistors. Perhaps you can find help on how to do this somewhere on this Google results page.
  13. hevans1944

    Head lamp set up

    Depends on the automobile manufacturer. I have seen it done both ways. My 2002 Ford Taurus Station Wagon illuminates the two filaments separately for low-beam and high-beam, but under certain circumstances will illuminate both filaments simultaneously. Suggest you check with a multimeter to...
  14. hevans1944

    Is it possible to replace keyboard LEDs with neon indicators and a single inverter?

    This can certainly be done, but just because it is possible doesn't mean it's practical. I see two problems: size and voltage requirements. The most common neon lamp suitable for use as a keyboard key-status illuminator is the ubiquitous NE-2, mentioned by @Audioguru in post #5. Suggest you...
  15. hevans1944

    What type of wire is copper wrapped around fluffy threads?

    It's called tinsel wire and is intended for crimp connections, not soldered connections. Lots more information at this Google results page. Tinsel wire is similar to Litz wire. Litz wire consists of individually insulated strands of round wire, usually woven to make a larger diameter cable for...
  16. hevans1944

    Help with a connector (Newb Question)

    Visit this Google results page and pick out something you like. The kind that folds the ribbon cable back on itself to form a strain-relief is my preference, but the straight-through and then squeeze to puncture the ribbon insulation also works well if not too many remove/re-insert cycles. You...
  17. hevans1944

    Piezo-charger

    Yes, the remainder of your comment was spot on. It is remotely possible that some natural large deposits of quartz, or other piezoelectric crystals, could respond to large stresses, such as may be encountered during an earthquake, with significant production of power... during the duration of...
  18. hevans1944

    Scratching noise on volume button

    Often, if you temporarily remove the knob, you can spray cleaner/lubricant into the potentiometer by directing the spray at the base of the shaft, where it enters the body of the potentiometer. Do this sparingly to avoid a mess, and test immediately after spraying by rotating the shaft back and...
  19. hevans1944

    Regarding Certification

    You should seek a certificate from a school that has ABET accreditation. If you eventually decide to seek employment abroad, an ABET-accredited engineering education will prove invaluable, and it is typically required for licensing as a professional engineer in the United States of America...
  20. hevans1944

    Piezo-charger

    Incorrect. Power is the rate at which energy is used. A watt-second (power multiplied by time) is a joule (energy). The piezo transducers of practical sizes do not produce enough energy (joules) to sustain an appreciable amount of power (watts) delivery.
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