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  1. hevans1944

    Wire antenna ripped out of remote control

    Most likely it was connected to one of the three pads located near L4, one of which is labeled ANT. Can you post a photo of the other side of the board showing this area?
  2. hevans1944

    19.2V Craftsman Battery Charger Dead. Please Help!

    I wouldn't waste my time trying to repair this. A new one is available for about fifty bucks. See all those SMD components on the reverse side of the circuit board? How would you go about testing (or replacing) the 28-pin ASIC? This is not your granddaddy's battery charger! It is a precision...
  3. hevans1944

    Concept: High Voltage Power Supply

    Clearly you need to do more "research" on exactly what and how a Tesla Coil works. Google is your friend here. There are scores of Tesla sites available that will help you. This is probably not one of them because the theory and design of Tesla coils is a rather specialized hobby. It can also be...
  4. hevans1944

    Help identify transformer

    This looks like a Ningbo Wanji Electronics Science & Technology toroidal power transformer. There are two secondary windings. A center-tapped 21-0-21 VAC winding (blue-black-blue) rated at 2.0 A and another 0-15 VAC winding (yellow-yellow) rated at 0.3 A. Good luck finding an American...
  5. hevans1944

    radiation pattern of yagi uda antenna is omnidirectional?

    It is directional with a beam width and front-to-back ratio dependent on the number of director and reflector elements. Google is your friend.
  6. hevans1944

    Lasers

    It would help greatly if you would describe what you intend to do with "a laser-gun." What range would you like to achieve? What happens at the target when it is illuminated by the laser beam? What is "a normal red laser beam?" Commercial beam-splitters are readily available but somewhat...
  7. hevans1944

    Arduino ultrasonic range detector

    Sounds like a fun project! Are you pulsing an ultrasonic transmitter transducer and measuring the arrival time interval of the echo? Do you use a narrow range gate that sweeps from minimum range to maximum range to allow you to acquire the echo? How does the range detector work? How do you...
  8. hevans1944

    Sending Files Over the Internet

    NS,S! That is the main reason for my unusually terse reply. Glad you jumped in!
  9. hevans1944

    making a tiny heat element

    You may want to consider using Kanthal wire instead of nichrome. This is popular among vapers who build their own heaters. It is readily available in small diameters. It operates on low voltages for reasonable lengths of wire and does not oxidize when heated to incandescence in open air. I would...
  10. hevans1944

    Sending Files Over the Internet

    Since all your computers connect to the Internet via the CISCO Linksys E900 router, you already have a secure de facto local area network (LAN). Now all you need to do is make your files sharable amongst all the computers on the network. Read the Windows or Mac documentation and the Linksys E900...
  11. hevans1944

    Looking for ideas

    Also keep in mind that the wire size used on commercial solder-less breadboards is limited in size to 22 to 24 AWG solid, not stranded wire. This is typically the size of the wire leads on1/4-watt resistors and small LEDs. If you try to force larger diameter wires into the breadboard it will...
  12. hevans1944

    Triac question

    It would help if you specified exactly which Velleman "4 channel running light kit" you are using. As far as I can determine, the four channels are independent in the sense that a lamp load on one channel has no effect on the other channels, whether the other channels are on or off. As for...
  13. hevans1944

    Heathkit IP20 Power Supply

    Sorry to jump in so late here... I am sick with something that makes me ache all over... just a cold I hope. Good thing I am fully retired now and can stay in bed, mostly. The OB2 is a "three-terminal" device, but two of the terminals, connected to the anode, are jumpered inside the envelope...
  14. hevans1944

    Pie Network , Transmitter Tuning and Loading Questions

    Ooops! Well, @Y2KEDDIE and I know that it's 365 μμF or 365 puffs. Thanks for catching that, Dave.:D
  15. hevans1944

    Pie Network , Transmitter Tuning and Loading Questions

    Yikes! Please don't kill a working Atwater Kent! I know of a fellow here in the Dayton area who restores old radios. He would have a heart attack at the mere thought of cannibalizing a working antique radio to repair or restore a non-working radio. He recently retired from Mendelson's...
  16. hevans1944

    transformers back to back - why won't work?

    I am having a hard time understanding how the primary and secondary currents can produce canceling magnetic fields at arbitrary currents. Neglecting leakage flux, don't these currents require that the core be able to sustain them without saturation, even though the fields cancel? Else, why try...
  17. hevans1944

    Pie Network , Transmitter Tuning and Loading Questions

    Thank you, @Y2KEDDIE for your reply. No offense taken for not wanting to pursue Ham radio at this time. To be honest, except for attending monthly DARA meetings and volunteering twice now at Hamvention® I haven't made much use of my new Ham license... a few on-the-air contacts on 80 m and 40...
  18. hevans1944

    transformers back to back - why won't work?

    The VA rating of the smallest transformer limits the maximum output power.
  19. hevans1944

    transformers back to back - why won't work?

    I spent several hours trying to find the answer to this question: what limits the power transfer capabilities of a real transformer? Bottom line appears to be losses creating unacceptable temperature rise. Couldn't find anything, except a side-bar reference on Wikipedia, that relates winding...
  20. hevans1944

    transformers back to back - why won't work?

    Both statements are correct. Magnetization actually decreases slightly as power transfer in a real transformer increases, because the primary current in the primary winding resistance produces a voltage drop that subtracts from the voltage creating the current for the magnetization of the core...
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