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  1. hevans1944

    Can’t find a 0.35 ohm 5% resistor anywhere

    Brand new Samsung (or other brands) televisions sell now at ridiculously low prices almost everywhere. Most often, it is more "cost effective" to just bin them and purchase a replacement instead of trying to repair them. Of course, if you are attempting a repair as a favor for a friend or as...
  2. hevans1944

    Fuse Cap identification

    Replacing fuse sockets can be a royal PITA because of their usually tight location. I would suggest using Vice-Grip pliers to crush the fuse holder body (be sure to remove the fuse FIRST) and separate it and its attached wires from the remainder of the fuse holder. You can then remove the nut...
  3. hevans1944

    Solenoid not working

    Absolutely! A picture (electrical schematic) can be worth a thousand words (or more). A properly annotated electrical schematic provides a common means of understanding and discussing the operation of a circuit. I have been guilty of trying to verbally describe circuits, but this should always...
  4. hevans1944

    Building DIY Vacuum tubes

    @Douglas Koo, it sounds like you know what you are doing. Please let us know if less expensive silicone oil works in a jet-type oil diffusion pump. Meanwhile, @George Schmermund mentioned a design he did for a small diffusion pump that works by entraining gasses on the cooled inner wall of the...
  5. hevans1944

    Building DIY Vacuum tubes

    This thread has been idle since July 6, 2016 when @George Schmermund last posted: I am retired now, but have worked with oil diffusion pumps and high-vacuum systems for more than thirty years, mainly with various small Varian models. My only experience with silicone oil was using it, with dry...
  6. hevans1944

    Induced current in a coil

    Hmmm. Let me venture a guess... you have a board game with tokens or objects arranged, more or less in a circle surrounding a central point, wherein a needle arrow, presumably mounted on a pivot to allow the needle to spin about the pivot, can be spun by a player's hand. Eventually the needle...
  7. hevans1944

    Induced current in a coil

    Yeah, but that would depend on why sensing the moving magnetized needle is important. So far, no response from @seza after the initial post.
  8. hevans1944

    Induced current in a coil

    Yes. Faraday's law of magnetic induction applies to any conductor subject to a changing magnetic field. Depending on the strength of the magnetized needle, how fast it moves while passing near the coil, and the number of turns of wire on the coil the resulting output voltage while the needle is...
  9. hevans1944

    Variable power to immersion heater by HF PWM the mains

    The worst solution is probably phase control because it introduces a LOT of harmonic frequencies on the mains. Gating the number of power line cycles over a fixed period of time, the "burst mode" solution mentioned by @Alec_t, is the method used by most consumer microwave ovens to control the...
  10. hevans1944

    Pressure Transmitter

    @Pushpraj7453: It would help us to help you if you would upload some images of the usual pressure transducer (like the one you don't want to use) along with a datasheet that describes the pressure transducer and the current-loop interface to the PLC. As @Harald Kapp and @Kiwi have warned you...
  11. hevans1944

    Does anybody here do photonics/optoelectronics?

    Learn as much as you can. Earning a PhD doesn't mean you stop learning. An advanced degree or two or three may actually hamper your getting a job in industry because some potential employers will think you are over-qualified, i.e., that you will expect more salary than they are willing to pay...
  12. hevans1944

    Pressure Transmitter

    Wow, @Pushpraj7453! You are just a fountain of useful information that some of us may have been able to use to solve your problem... if only you would tell us WTF you are trying to DO! Oh, really? Just unplug the pressure transducer and replace it with a resistor? What is that supposed to do...
  13. hevans1944

    Basic electronics advice needed, regarding room temperature quantum bit design.

    Oh, really? There has been some recent work done in this area, using laser-excited point-defects in diamond crystal lattices and in silicon carbide crystals. Anyone interested in that could start here. I don't see any practical applications of this yet. Qubits tend to "evaporate" because of...
  14. hevans1944

    Stepper Drive Optimization

    I would use an up/down binary counter to count up the pulses sent to the driver, then after the 500 ms delay, reverse the motor controller direction and the direction of the up/down counter and send pulses until the counter under-flowed or reached zero. A relatively simple hardware solution...
  15. hevans1944

    converting a high amperage battery to lower amps without reducing voltage on a DC motor.

    My wife had me build a small shaker box using scrap lumber and hardware cloth stapled to the lumber. This was used to separate "river rock" from dirt after an "idiot" in-law dug up the stones and dumped them on our concrete driveway, dirt and all. No motor necessary, we just sprayed water on the...
  16. hevans1944

    Understanding basic passive components: resistors, capacitors, inductors.

    Thank you, Bertus. That excellent link covers everything I was going to write about, except possibly some background history on the development of the passive components. That said, maybe I should just give up on ever finishing the project since Charles Platt has pretty much covered everything a...
  17. hevans1944

    Need a new multimeter - any thoughts

    Thanks, @bertus! Found it, changed it, works again as before. You can of course still highlight some text in the usual way, and then use the link icon to insert a web page you want to link to. But that means you have to go to that web page and highlight and save its address, an extra step the...
  18. hevans1944

    Need a new multimeter - any thoughts

    If you click on the link, you are sent by Electronics Point to a website that features an 8-pin component in a plastic DIP, not a multimeter. Can someone PLEASE TURN OFF this gratuitous linking of irrelevant "information?"
  19. hevans1944

    Where could I salvage an LM317 Voltage regulator?

    Thanks, Harald, but I saw it (I think) today in an e-mail by @zayman who posted automagically yesterday, May 6, 2021. It was a really nasty rant, posted on an almost two year-old orphan thread, by someone who joined EP yesterday. The OP, @Raser, (Ben) posted just once and has not been seen...
  20. hevans1944

    Energy storage - alternatives to batteries

    Everyone involved with electric vehicles, whether that be Tesla's full-sized tractor-trailer behemoths of the highway, or 1/24-scale, remote-controlled models of popular ICE (Internal Combustion Engine) vehicles... all would like to do it another way... without batteries. Batteries are not an...
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