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  1. hevans1944

    Could use some experts insight into identifying connector type.

    Just goes to show ya that you doesn't necessarily need to be an egg-spurt to find useful things here. Plus, I think my photo is prettier, even if it doesn't have the right number of connector contacts and was posted ten minutes after your post #3. So there.:D
  2. hevans1944

    Basic electronics

    Assuming your calculations are correct (I haven't checked them), where are you going to get more than 9000 amperes at 230 volts to feed into your nichrome heater rods? That's somewhere north of two million watts! It sure isn't going to come from a normal Danish wall plug! And where are you going...
  3. hevans1944

    Could use some experts insight into identifying connector type.

    Maybe something like this?
  4. hevans1944

    gas detection system

    Well, who knows what the right track is? Or whether there even is a track. The OP didn't say why he wants to "detect leaks" or where the leaks might occur. The instrument he cited is a rather expensive survey meter typically used by hazmat teams and first responders to display quantitative...
  5. hevans1944

    LC Oscillator

    "a variable frequency range of 1 MHz to 1.5GHZ without using any microchips, timers or op-amps" is beyond the capability of most experienced professionals if an LC network must be used to tune it. Such a wide range is usually the province of a direct digital synthesized oscillator.
  6. hevans1944

    Need help : Steel conductivity vs LED

    That circuit you posted (with your correction that each wire goes to an LED in series with a resistor) will test to see if any of the wires are grounded to the tube. If an LED lights, that wire is shorted to the tube. If you want to test continuity of each wire (from end-to-end), plug one end...
  7. hevans1944

    Microcontroller controlled by pushbutton for LED flashlight

    I thought I would bump this thread to let everyone know where I am with programming the PIC10F206. I think I mentioned in another thread that I finally realized that I had to disable the comparator to use its two input pins for digital I/O. So I now have a simple program that reads a push-button...
  8. hevans1944

    Need help : Steel conductivity vs LED

    Yes, you need to make a "continuity checker" consisting of a 9V battery, a 330 ohm 1/2 watt current-limiting resistor, and an LED. The long leg of the LED is the positive (anode) terminal and connects to the + terminal of the battery. The other leg of the LED connects to one end of the resistor...
  9. hevans1944

    I've been tagged

    I like to use tags for attribution of good advice, but if the advice wasn't provided in the current thread I try to provide a link to the original thread so everyone can go read all about it.
  10. hevans1944

    gas detection system

    I just remembered that mercaptan (methanethiol) is often injected into utility natural gas supplies as an aid and warning of pipe leaks, because natural gas is odorless and colorless. Here we rely on the Mark I odor-sensing system, our noses, to determine that a leak is present. Same principle...
  11. hevans1944

    gas detection system

    Sometimes, someone hands us an "impossible" problem to solve with the expectation that we will fail. And sometimes we do fail because no solution to the problem exists. But detecting a nitrogen leak in the presence of atmospheric nitrogen is just very difficult, not impossible. One possible way...
  12. hevans1944

    More efficient LDR "dark" switch?

    Modeling is good, I guess, but you can't beat plugging in real components and applying power to see if it works. It's when it doesn't work that I would turn to modeling to perhaps find out why. When a circuit doesn't work, but the SPICE model says it should, what do you do then? You go back to...
  13. hevans1944

    gas detection system

    Small nitrogen leaks are virtually impossible to detect because of its strong background presence in the air. You would need to get a "sniffer" probe that sucked in the nitrogen leak with a vacuum pump and then the detector would have to suppress the background nitrogen level the sensor would...
  14. hevans1944

    Radio reception

    Sorry, Deigh, you must have an antenna outside attached to a wire, usually coaxial cable, leading inside to get a decent signal inside the type of building you describe. Remember the old "rabbit ear" antennas that used to sit on top of the TV? People would hang aluminum foil on them and bend the...
  15. hevans1944

    More efficient LDR "dark" switch?

    I really like the idea of using the two analog comparators that are built-in to the 555 timer, as suggested by @Harald Kapp, to obtain hysteresis. You don't have to use the timer functionality of the 555, and in this case you aren't. The comparator inputs do require some current to function, but...
  16. hevans1944

    Basic electronics

    Welcome to Electronics Point @Anders Lund! I think we may have a communications problem. None of what you posted makes any sense. For example, you state that the two resistors are 1.27 x 10^-7 ohms heating elements. This is nonsense, as that would be 0.000000127 ohms, or 0.127 μΩ. The current...
  17. hevans1944

    More efficient LDR "dark" switch?

    I currently have a house full of grandchildren running around, helter-skelter, here in Virginia Beach. When (if) things settle down, I will try to work on your problem. Realistically, that may not be until after I return to Dayton... <sigh> Plus, it was in the high 90s today (felt more like over...
  18. hevans1944

    gas detection system

    Yeah, the Multirae Pro is quite the thing for gas detection... and gamma rays, too! Every prepper needs one. However, it's sensors are only sensitive to the particular gasses they are designed to detect. If you need to detect a gas that your current sensor isn't sensitive to, you need to change...
  19. hevans1944

    gas detection system

    Thank you for answering part of my questions in post #6. I can understand you want to detect leakage of CO2, natural gas, and LPG (liquified petroleum gas)... but nitrogen? The air we breathe is 80% nitrogen. How do you expect to detect a nitrogen leak (presumably from a cylinder of gas or a...
  20. hevans1944

    gas detection system

    Please answer my questions in post #6. There are calibration kits available for gas detectors so it is easy to find out "is the detector detecting accurate gas leak or not".
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