Search results

Search Forums New Posts
  1. hevans1944

    Water level sensor

    Are you thinking of measuring current between two probes with variable sensitivity to the conductivity? An auto-ranging circuit would seem to be appropriate for this. Use solid-state analog switches to control the sensitivity, or perhaps use DIP switches to set the sensitivity if the water...
  2. hevans1944

    12V relay with 9v battery_not working

    Yes, use 12 V battery. Just connect eight AA or AAA dry cells in series-aiding. Pay attention to polarity! Positive of one cell connects to negative of next cell, daisy-chained until all eight cells are connected together and you have one positive and one negative lead attached to the first and...
  3. hevans1944

    Frankenstein's Components.

    I vote for recreational pharamceuticals. Isn't "levitation" something you do with yeast to make bread rise?
  4. hevans1944

    FSAM75sm60A Fault Protection Timing Circuit

    Yep, a lot of my "someday" DIY projects have fallen by the wayside since the Chinese started making stuff dirt cheap. But I will continue to piddle around with things, simply because I enjoy doing so. I bet you will too! Thanks for the info on three-phase inverters for motor drivers. When I was...
  5. hevans1944

    FSAM75sm60A Fault Protection Timing Circuit

    I like this chip and was considering it for large stepper motor drivers. If I understand it correctly, you can monitor the voltage on pin 10 to get a measure of output load current, but its main purpose is feedback into the chip to shut it down if there is a current overload condition. Nice...
  6. hevans1944

    Microstrip Antennas Manipulation

    Maybe. But I thought trolls mostly hang around and post endless off-the-wall questions and argue. This one simply popped up, deposited a few pearls, then left. He continued posting here on a (probably) related topic.
  7. hevans1944

    Insights On Powering Patch Antenna In Cell Phones

    Here is a block diagram of recent cell phone technology. You can find it here. Also many links to cell phone theory of operation can be found here. Remember, Google is your friend in matters both simple and complicated. Please note that EACH of those blocks in the above diagram contains...
  8. hevans1944

    Tweaking an industrial ozone generator help (HV)

    A neon sign transformer is overkill for ozone production. Try cutting the plate you Araldited in half with a ceramic-cutting abrasive disk. Use plenty of water for lubricant and cooling. Try out the smaller plate to see if it arcs over at the cut end. Your epoxy may not be a good insulator at...
  9. hevans1944

    FSAM75sm60A Fault Protection Timing Circuit

    On page 8, Figure 6, the values of Rsu, Rsv, and Rsw vary from 0 to 0.030 Ω with appropriate current limiting Rsc values diminishing from 27 Ω down to about 2 or 3 Ω as the "ground" resistance in each of the three phases increases. The Rsc resistor connected to pin 10 is NOT in parallel with the...
  10. hevans1944

    how the zener functions in the circuit?

    It will prevent the relay from energizing if the power supply input voltage is too low.
  11. hevans1944

    LM317 2N3055 Variable Circuit Problems

    Three significant figures is all you need for most electronic calculations, So, 13.3 ohms which (depending on the circuit) would be rounded up or down to the nearest "standard" value, which depends on allowable tolerance in resistance value. Google that. I have no idea if the value you...
  12. hevans1944

    Designing a Time Delayed Relay

    Believe-it-or-not, I had never heard of Planet-Source-Code.com until your post! Thank your for that. So, I visited their website, joined up, and now am ready to upload a killer app for all the world to see... as soon as I find my "round tuit" and write it.:cool: Geez, this thing has been around...
  13. hevans1944

    I need a really small, really smooooth motor...

    I like your concept. I don't recall ever seeing anything like it. And absolute encoders get quite expensive as the resolution increases, whereas your concept doesn't! But here are a few suggestions... do away with the "ring of light" because it is an unnecessary complication. Mount an LED on...
  14. hevans1944

    Microstrip Antennas Manipulation

    The OP posted his question on August 4 and has not been seen since. Who knows what he wants to do? As I read it, it sounded like programmatic control of microstrip parameters. It also looked like a snippet taken from a published paper on the subject, perhaps a patent disclosure. In any case...
  15. hevans1944

    Designing a Time Delayed Relay

    Years ago a "professional" told me that BASIC was not a good programming language and I was wasting my time with it. This was the first computer language I learned and I loved it! So easy to write code and get immediate gratification that I had done it right. The so-called pro sniggered at my...
  16. hevans1944

    I need a really small, really smooooth motor...

    It's not so much backlash as gear tolerances when driving in the same direction all the time. All gear trains of whatever type will have minor variations in the tooth engagement and gear eccentricities. Even the finest watches will exhibit these "defects" if inspected closely enough. It's just...
  17. hevans1944

    LM317 2N3055 Variable Circuit Problems

    IIRC, no capacitor is required on the output of the LM317, although a 10 μF from the ADJUST terminal to ground can be inserted to reduced ripple in the output. Try to keep this circuit as simple as possible until you get it right. Download and read the LM317 datasheet because it has application...
  18. hevans1944

    I need a really small, really smooooth motor...

    Could you elaborate a little bit on what you are trying to DO? How does the disk serve as an optical shutter? A slot? Blades? What percentage of the time is the optical path open during each revolution? Is this for timing or synchonization or is there some other purpose for the "optical...
  19. hevans1944

    Tweaking an industrial ozone generator help (HV)

    AFAIK Teflon cannot be glued by ordinary human beings. You would have to use a pressure plate to secure it, maybe use the corner posts and cut an aperture in the sheet of Teflon: Teflon backed with aluminum, stainless steel, or fiberglass circuit board material to hold it in place might work...
  20. hevans1944

    How is IOT different from Embedded Systems?

    IoT, or Internet of Things, is a networking concept where two or more (often a LOT more) devices all communicate with each other. A WiFi module may or may not be included in the mix, depending on how those individual devices connect to the Internet. In any case, some sort of embedded system is...
Top