Search results

Search Forums New Posts
  1. hevans1944

    1.5 volt bulb won't light in my circuit newbie

    Harald, you are right of course. It does no harm to see what happens next, and perhaps things will sort themselves out. Meanwhile, I have a comment on an earlier comment @stspringer made... That's a pretty good attitude. Many of us here began careers in electronics or electrical work as...
  2. hevans1944

    1.5 volt bulb won't light in my circuit newbie

    @stspringer is perhaps now stuck in a loop, where he believes a current-limiting resistor is both sufficient and necessary to control the LED current. As Bob, Bluejets, and I have been trying to explain, a resistor may be sufficient but it it is never necessary to control the LED current, just...
  3. hevans1944

    1.5 volt bulb won't light in my circuit newbie

    Yes, you could, but you are missing the whole point of the video. You don't need, and should not use, resistors to set the current passed through one, two, three... or however many... LEDs! That you used resistors in the beginning was so you could learn about how LEDs work, how much voltage...
  4. hevans1944

    1.5 volt bulb won't light in my circuit newbie

    @stspringer: I think it is very admirable that you are taking a "hands on" experimental approach to learning electricity and electronics. You are in the process of learning some valuable lessons about voltage dividers and practical values of the resistance associated with them. Take careful...
  5. hevans1944

    Waterproofing Ultrasonic Sensor?

    @Nilesh579: And this is an amazingly old thread from March 21, 2013.
  6. hevans1944

    The simplest definition of VOLTAGE you can come up with

    Apology accepted. It's not that you have offended me (my skin has grown pretty thick by now), but that you have surely wasted the time of both me and other members of this forum by posting "questions" for which you can easily find answers using search engines... that's what they are there for...
  7. hevans1944

    Micro hydro-electric generator help

    Thank you for your service. My family also served, and some of us continue to serve today. I have the utmost respect for our military, who put themselves in harms way to help preserve our freedom and our nation's sovereignty. A combat engineer, as a trained infantry, is right up there along the...
  8. hevans1944

    Micro hydro-electric generator help

    Personal attacks? I simply made a few truthful observations in an attempt to show you the error of your ways through absurdity. Did you miss the biology class that demonstrated hamster generation of electricity? As I approach age seventy-five with failing health, I find my time is too valuable...
  9. hevans1944

    Micro hydro-electric generator help

    It never ceases to amaze me the number of otherwise well-educated, i.e., successful enough to afford a (fly-in?) Canadian wilderness fishing expedition, who nevertheless don't have a clue about electricity. Perhaps they imagine electrical power, in sufficient quantities to operate a fish...
  10. hevans1944

    The simplest definition of VOLTAGE you can come up with

    Of course it did, but that factoid doesn't appear to faze an uneducated troll like @gubavac111. Best not to pay the troll any mind and go on about your business here and elsewhere. Which, on that fine note, I will say it's good to see you still alive an' kickin' @Ratch. This forum isn't nearly...
  11. hevans1944

    The simplest definition of VOLTAGE you can come up with

    It means there is an alternating current (AC) with a root-mean-square or rms potential (voltage) of 220 V available between the two lines that can do work on a resistive load applied across the two lines. For example, turn the shaft of a motor, illuminate a light bulb, heat a water heater... the...
  12. hevans1944

    The simplest definition of VOLTAGE you can come up with

    Voltage is always measured between two and only two physically separated points in space. Voltage is a scalar quantity, having a magnitude but no preferred direction. When a voltage potential difference exists, it creates a vector electric field, the negative of whose gradient is a measure of...
  13. hevans1944

    Help select suitable Mosfet for driving relay.

    Given the state-of-the-art in Digital Storage Oscilloscopes, and their relatively inexpensive pricing, it is incomprehensible to me why anyone who is serious about electronics today doesn't already own one, along with the knowledge and experience necessary to use it to detect parasitic...
  14. hevans1944

    Help select suitable Mosfet for driving relay.

    So, have you figured out why you are bricking BJT and MOSFET driver transistors yet? This business with parasitic oscillations did not occur very often in my experience, but when it did happen it was deadly quick in its ability to kill semiconductors when there was sufficient power available to...
  15. hevans1944

    Lead acid battery

    If you are buying mainland Asian parts, who knows what is inside the can? I've seen YouTube horror videos, made a few years ago, that reveal the inside of D-size and C-size cans mostly filled with sand or talcum powder, plus something that sort of resembles a dry cell chemistry AA or smaller...
  16. hevans1944

    Help select suitable Mosfet for driving relay.

    It doesn't matter because the resistor is not connected to the relay. And this is most likely a non-issue for your relay driver. Although parasitic oscillations are the bane of experimental setups, they are generally solved by improving the layout and circuit interconnections. What @WHONOES is...
  17. hevans1944

    Flyback transformer?

    Swapping does play a role in troubleshooting, but only after troubleshooting has narrowed down possible causes of failure to several candidates. Unfortunately, it is often impossible to remove a component without seriously damaging it, or the circuit board on which it is mounted, so...
  18. hevans1944

    Attract fish by sound, light or anything else

    And I also agree that the title of the thread bears no resemblance to the homework topic, if the topic is how to build a depth meter. You need to do a LOT of research about how to use acoustical methods to locate the depth of an object in water, i.e., commonly known as active sonar. Come back...
  19. hevans1944

    Attract fish by sound, light or anything else

    Why re-invent this particular wheel? There are commercial units available everywhere. Or you can try to build it yourself.
  20. hevans1944

    Flyback transformer?

    Does it appear that I may have hurt your feelings, Snowflake? Maybe. I am just a crotchety old man, but I learned to identify incompetence a long time ago. I have zero tolerance for incompetence because it is a huge waste of time and money for everyone involved. I asked three questions of you in...
Top