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  1. hevans1944

    Solenoid amperes ???

    The "correct amperes" is whatever the solenoid current is when 12 V DC is applied. Put a multimeter in series with the coil and select the 10 A range. Energize the coil from a 12 V DC supply (such as a fully charged automobile battery) and observe how much current is supplied to the coil...
  2. hevans1944

    What's the "danger zone" for tesla coils?

    For you, either one would be extremely dangerous because clearly you don't have a clue how a Tesla coil works. Turns ratio is mostly irrelevant because the primary AND the secondary of a Tesla coil are operated as resonant tuned circuits. To remedy your lack of knowledge and understanding visit...
  3. hevans1944

    Endoscopy Light Source

    Endoscopy light sources consist of a bundle of optical fibers tightly encased in a flexible sheath, illuminated on one end with a light source and polished flat on the other end. Until LEDs became widely available, the illumination source was an incandescent lamp. As @kellys_eye said, Google...
  4. hevans1944

    Correct Motor Help

    Try this link.
  5. hevans1944

    Relating tesla coil power to plasma bulbs?

    IIRC, neon sign transformers (NST) are limited to 7500 volts from the "hot" wire secondary to "ground". Some have two "hot" wires, representing opposite ends of a center-tapped secondary, with up to 15000 volts between the two terminals. The center-tap is grounded, limiting the voltage from...
  6. hevans1944

    ebike with speaker amp as a watt amperage is it possible

    Excellent example of the GIGO principle: Gibberish In, Gibberish Out. Posting in all lower case letters, with the only punctuation being the ellipsis (...) and three question marks (???), causes my attention to wander immediately to the next (intelligible) thread, pausing only long enough to...
  7. hevans1944

    Successful Stanford Research SR530 lock-in amplifier repair

    MLCC caps for power-rail by-pass applications sounds like a good alternative to tantalum caps, maybe "backed up" with an aluminum electrolytic or two if this is a retrofit and there is room available. I have in my "junque box" somewhere a few dozen or so tantalum capacitors of uncertain voltage...
  8. hevans1944

    Successful Stanford Research SR530 lock-in amplifier repair

    Excellent idea. I haven't done any work with optical choppers since the 1970s, but do recall they came in several variations and were quite expensive, considering that "all" they did was spin a disk. A DIY optical chopper should be eminently practical to build today using...
  9. hevans1944

    Successful Stanford Research SR530 lock-in amplifier repair

    Congratulations! You may now be prepared to verify and repeat an "experiment" I did in the mid-1970s to detect the presence of people (warm bodies) using a single uncooled pyroelectric detector, a simple two-bladed light chopper, and a pricey PAR lock-in amplifier. Piece of cake to do this today...
  10. hevans1944

    Successful Stanford Research SR530 lock-in amplifier repair

    By the time you get done re-engineering that little beastie with better capacitors it should be worth twice what it sold for when new! Well... it should be, but you know how that goes... I didn't realize those tantalum capacitors were so prone to failure. Mostly avoided them anyway because of...
  11. hevans1944

    Successful Stanford Research SR530 lock-in amplifier repair

    Ummm. Celestial music (often buried in noise) requires a different technique to recover than a simple lock-in amplifier. You need a correlating detection system plus an original, low noise, recording of the signal you are trying to recover... preferably a digital rendition... and patience to...
  12. hevans1944

    Powering an LED from a triboelectric nanogenerator

    Sounds like another "solution" looking for a "problem" to solve.:cool: GLWT.
  13. hevans1944

    Successful Stanford Research SR530 lock-in amplifier repair

    Steve's new toy does a fine job of recovering a very tiny AC signal buried below the noise floor, provided that signal is coherent with a reference signal. A Jimi Hendrix guitar riff is normally considerably larger than the noise floor, so a lock-in amplifier is not necessary. Umm. The label on...
  14. hevans1944

    How to measure diesel tank level by pressure sensor, tank area and diesel paramenters

    Is Musk selling seats or taking reservations for a Mars excursion/vacation trip yet? I noticed he sent a vehicle ahead to secure ground transportation.:rolleyes:
  15. hevans1944

    How to measure diesel tank level by pressure sensor, tank area and diesel paramenters

    Agreed. I don't think anyone deliberately tries to drive until the tank is virtually empty and the vehicle is "running on fumes"... with the possible exception of teenagers, who are generally loath to fill up (or even add gas to) the family car on their own nickel. My wife keeps an eye on the...
  16. hevans1944

    How to measure diesel tank level by pressure sensor, tank area and diesel paramenters

    No, it isn't. Every minute not spent driving on the road represents a cost that cannot ever be recovered. That is why truck drivers back in the 1950s took those "little white pills" to stay awake and "on the road." The lyrics to the song "Six Days on the Road" provide some insight into what the...
  17. hevans1944

    How to measure diesel tank level by pressure sensor, tank area and diesel paramenters

    Not sure what the economic incentive to the manufacturer would be. As you noted, most drivers simply "fill 'er up" when re-fueling, and logbook records and receipts could be (and are) used to verify usage and track miles-per-gallon or kilometers-per-liter fuel efficiency, Unless the trucking...
  18. hevans1944

    How to measure diesel tank level by pressure sensor, tank area and diesel paramenters

    I just happened to dig out of the trash at work the other day a trade magazine, the May 2018 issue of "Fleet Maintenance -- All Maintenance, All Management, All Vehicle Classes, All the Time." The main article discussed the case for on-site fuel management. One option is on-site delivery of...
  19. hevans1944

    Capacitive reactance affecting voltage divider output

    Depending on your goal, and why you placed the capacitor in series with the voltage divider, if your desire is to minimize the capacitive reactance effect of the capacitor on the resistive voltage divider, then you will require as large a capacitance as possible. Allowing |Xc| = 1 / (2 π f C) to...
  20. hevans1944

    Capacitive reactance affecting voltage divider output

    I inserted an extra "O" to make it "Waste Of Our Time" because there have been many responders playing "what if" games on this thread.:eek: I apologize for the additional confusion, but this thread is still, IMHO, a FWOT though.
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