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  1. hevans1944

    Physical difference between low/high transformers?

    Since the primary inductance is an increasing function of frequency, you might have trouble getting enough current switching it fast. The "fly-back" voltage would also be larger for any given switching current. The hysteresis losses will be terrible. That's why high-frequency cores use...
  2. hevans1944

    Merry Christmas

    Yes! Merry Christmas and Happy Holiday wishes from here in sunny and warm Florida! Plenty of Gulf Coast white beach-sand to help celebrate a "White Christmas" sans snow shovel.:D I'm lovin' it here!
  3. hevans1944

    Modifying MOT to get 40KV

    Most microwave transformers will only provide a few thousand volts (instead of the higher voltage you need) unmodified, but the key is to rectify the AC voltage with DC voltage multipliers to get the DC high enough for plasma work. It is easy to build Cockroft-Walton (C-W) voltage multipliers...
  4. hevans1944

    Anyone have any oscilloscope recommendations?

    Since the 1960s, when I first built my EICO 460K oscilloscope, I have acquired several used Tektronix oscilloscopes. The EICO was "pretty good" for TV work, but it lacked a triggered sweep and had other shortcomings. So, as soon as I realized there were better alternatives, I went looking for...
  5. hevans1944

    Modifying MOT to get 40KV

    Hmm. 40 kV at 20 mA is 800 watts. What are you going to do with all that power? Why not just use the MOT "as is" since it already has a high voltage winding? In combination with a variable transformer at the input and a voltage doubler at the output, you should be able to get your 40 kV DC...
  6. hevans1944

    Anyone have any oscilloscope recommendations?

    If you do decide to purchase it, make sure you order the kit version that has the SMD components already soldered to the circuit board. It is a real PITA to place and solder those itsy bitsy teeny weeny parts. There is also a newer model available at a slightly higher cost that includes a...
  7. hevans1944

    Anyone have any oscilloscope recommendations?

    That's why I recommended the JYE Tech kit oscilloscope. It is inexpensive (less than fifty bucks, even after you add a wall-wart power supply and shipping) and has adequate sensitivity and bandwidth for audio applications. It offers a really cheap entry point and allows the user to learn how to...
  8. hevans1944

    Anyone have any oscilloscope recommendations?

    I bought a Hantek DSO5202P earlier this year that I like a lot. It was on special sale with free delivery. You can check it out here. What you get depends on what you want to do and how much you are willing to pay. An inexpensive kit 'scope is available and that's what I would recommend as a...
  9. hevans1944

    Where to get sensor contacts?

    You could try to make your own electrodes using the snap connectors on a defunct "transistor radio" battery. Just use a pair of diagonal cutters to peel away the soft metal jacket holding the contacts in place. Discard everything else. The contacts should lift right out and you can then use the...
  10. hevans1944

    24 VAC to 12 VDC

    I have just this week finally moved to my new home in Venice, Florida, but I haven't forgotten about you. It will take awhile to get setup here for electronics work, but since you said you had already hired someone to handle your electronics work, further examination of your secondary clock...
  11. hevans1944

    Two HDMI-splitters one after another

    You could try it, but I think it would be very iffy if the cables are lengthy. The HDMI signal is wide-band and designed for point-to-point connection between a single source and a single display over short distances. The HDMI specification doesn't specify a distance, just the signal quality...
  12. hevans1944

    What is the resistance and wattage of this resistor

    Yes, go to a "big box" home improvement store or even Radio Shack and purchase an inexpensive digital multimeter. If you are serious about electronics you can "upgrade" to a more capable multimeter later. Expect to spend about twenty bux to get started. BTW, those solder-less breadboards you...
  13. hevans1944

    Hello all

    Welcome to Electronics Point, Kathy!
  14. hevans1944

    Inductors and capacitors

    @Chr1s This is a self-help forum! That means we help those who help themselves. Your original post was a good question, and @Harald Kapp gave you a good response; however, too good in @davenn 's opinion (which I also happen to share). Please read again Dave's post #2 on this thread. Make Google...
  15. hevans1944

    Looking for a part

    makes 3 of us. GIGO principle applies.
  16. hevans1944

    Error in Schematics or am I missing something?

    Yes.
  17. hevans1944

    Error in Schematics or am I missing something?

    If the intent is to alternately light the LEDs when the push-button switch is actuated and released, then the schematic is wrong. The positive from the battery must connect to the moving contact of the relay, which is pin 5. The anode of the left-side LED on the schematic must connect to the...
  18. hevans1944

    Res dip pack multisim

    I haven't used multisim (yet), but since the part is just seven resistors that happen to be in the same package, why not just "model" it as seven discrete resistors? Is the pin-out of the resistor pack important to multisim modeling?
  19. hevans1944

    LED Driver Wattage Question

    Aww... a year to figure out a SMPS? You buy a chip, an inductor, a few capacitors and download an Instructable.:rolleyes: Might take a few days to get it working, so purchase extra parts... just in case.
  20. hevans1944

    Off grid and popping capacitors on electronics

    Google should be your friend. Look at this results page.
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