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  1. hevans1944

    clever vibration motor driver?

    Not so wonderful about the raw deal that Loebe Julie received while working as an engineer for Columbia University. This is still common practice today. Basically, as an agreement for employment, you sign away your intellectual property rights to your employer. Everything you do for them becomes...
  2. hevans1944

    Filter Choke for power supply

    Yep, I agree. Go fer it!
  3. hevans1944

    Filter Choke for power supply

    The LM-13 instrument uses four 45 V batteries to provide 180 V.
  4. hevans1944

    clever vibration motor driver?

    @dorke : thanks for the link! I just spent several hours reading some of the PDF. Yikes! I especially liked Bob's anecdote about how Bob Widlar made sure defective parts that bedeviled him in a prototype circuit would never come back to be re-inserted in another circuit: he placed them on the...
  5. hevans1944

    Transforming hammer help

    @keyblade_crafter : re-circulating ball bearing slides are my favorite for linear motion, but I didn't realize they are now available so inexpensively! Maybe I will resurrect those stepper motors I have stashed away somewhere and build an X-Y-Z something or other... maybe a CNC laser cutter with...
  6. hevans1944

    Filter Choke for power supply

    You will probably also want a 12 VDC power supply to replace the two series-connected "A" batteries used for filament power. Would NOT recommend using two series-connected 6.3 VAC filament secondary windings on your power transformer for this purpose, unless you don't mind a little 60 Hz "hum"...
  7. hevans1944

    clever vibration motor driver?

    That's a good idea, Chris, but my complaint was that solderless breadboards only accept a narrow range of wire gauges, typically 22 to 24 AWG, and therefore require soldering on an acceptably smaller gauge wire to thicker diameter leads. If you use the "hang it all out in air" method of...
  8. hevans1944

    Transforming hammer help

    Here is another velly interesting actuator possibility: so-called muscle wire or nitinol, a nickel-titanium alloy with very unusual properties.
  9. hevans1944

    Transforming hammer help

    I think you need to better visualize how this would work before trying to power it up. As @shrtrnd suggested, a mechanical model would be my first step in a design. You can add electro-mechanical actuators later once you have a better idea of the size and weight limitations that will determine...
  10. hevans1944

    Controll for Seven-Segment-Displays

    That Italian "work around" is clever. However, Maxim makes several common-anode LED display drivers. The ICM7218A and ICM7218C are common-anode drivers and the ICM7218B and ICM7218D are common cathode drivers. I have attached a datasheet that describes all four versions. Go here to see other...
  11. hevans1944

    Zener Diode

    @SHAIK MAHABOOB BASHA : Welcome to Electronics Point! This thread is (or was!) about zener diodes. It is considered impolite to jump into a thread with a new topic as you just did. This is called hi-jacking a thread. People do that all the time in forums, and I am guilty of it myself, but we...
  12. hevans1944

    Filter Choke for power supply

    It has been many years, circa 1966, since I constructed a plate power supply using a 5R4-GY vacuum tube rectifier, high-value electrolytic capacitors, and the biggest choke I could get my hands on. I think it was about 10 Hy and good for at least 1 A. This was the power supply for my 75 W...
  13. hevans1944

    Homemade diode

    If you have access to old monochrome or color vacuum tube televisions, there are HV vacuum tube diodes in the CRT anode power supply. If you have access to more modern color televisions, there are solid-state HV diodes in the CRT anode power supply. It is virtually impossible to make an HV diode...
  14. hevans1944

    Do I need a heatsink? How big?

    Please finish Section 6.
  15. hevans1944

    Diode Power and Heat Sink

    @mityeltu I said it would be difficult. The heat transfer from heat sink to ambient is not an easy problem to solve, but you are on the right track. First, assume the diode junction is running at maximum temperature, 200 C, and the that somehow the heat sink temperature can be held to 50 C...
  16. hevans1944

    Diode Power and Heat Sink

    You need to know the thermal resistance from junction-to-case and the thermal resistance from case-to-heat sink. This information in in the datasheet. Then you need to know (or estimate) the thermal resistance of heat sink to ambient air temperature, a difficult thermodynamics problem in...
  17. hevans1944

    Zener Diode

    You will get a clipped sine wave. Is this a homework problem? Did you already ask this question as member "stones" in All About Electronics forum here? It is considered impolite to cross-post to two or more forums. The question was answered most adequately in your All About Electronics post.
  18. hevans1944

    Dumpload system

    Why don't you modulate the water flow to the turbine with a servo-controlled gate valve? Can the water be diverted away from the turbine?
  19. hevans1944

    latching pushbutton help

    I liked your sketch.
  20. hevans1944

    active usb cables?

    CAT5 is Ethernet cable. USB protocol is an entirely different animal. The Instructables web site is the blind trying to lead the blind; I would not consider it a reliable place for "research" information. The method cited in the link will not work to extend a USB cable.
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