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  1. hevans1944

    AC circuit (120v single phase) smooth to a10 sec. average voltage sine wave

    That's easy. Just build a very low distortion sine wave generator and phase-lock it to your "glitchy" sine wave. Now subtract the two waveforms, leaving only the "glitches" to record. If the "glitchy" input also varies in amplitude (power line surge and sag) you will also need an automatic...
  2. hevans1944

    AC circuit (120v single phase) smooth to a10 sec. average voltage sine wave

    Any passive linear network involving capacitors and inductors will change the original waveform after "smoothing" it, making it impossible to meaningfully subtract the original waveform from the "smoothed" waveform. Again, I ask, what is the end-game here? Why do you want to do this?
  3. hevans1944

    Electronic Swing Device

    Park swings... at least the kind you sit on... swing on a horizontal axis that is parallel to the ground. So, you want to hang your sign vertically from a horizontal rod (axis) and make it swing to and fro plus and minus twenty degrees or so? Sort of the way a pet-entrance door swings up and...
  4. hevans1944

    AC circuit (120v single phase) smooth to a10 sec. average voltage sine wave

    You will already have the "live" and "averaged" values (as digital representations) in the two FILO buffers. All you need to do is subtract the first buffer (inverting the sine wave) from the second buffer, point by point, to obtain what you seek. All in real time of course.
  5. hevans1944

    AC circuit (120v single phase) smooth to a10 sec. average voltage sine wave

    And the way to do this... is not simple! You want to digitize and store a goodly number of samples per cycle in a random access or serial memory device. If this is a real-time application with a running average, you discard the last sample when the next sample comes in. A FILO (first in, last...
  6. hevans1944

    simple circuit drawing software

    Someone here recommends using plain ol' Microsoft Paint, but I can't find the thread. He even provided a set of ready-made symbols to use, and you can add your own. Of course any of the free software mentioned by @Supercap2F and @BobK will do much more than make pretty-print schematics: design...
  7. hevans1944

    PWM solenoid use

    That's true too, and if you don't... my acronym applies.
  8. hevans1944

    Beginner question: Can I convert speed fan switch to three?

    When I was still employed, one of the PhD scientists would connect a table-top 10A Variac to a geared synchronous clock motor to rotate his coating targets inside a physical vapor deposition (PVD) vacuum chamber at a variable speed. The motor looked like this: The image above was copied from...
  9. hevans1944

    Component ID

    Martin, why not whip out your VOM and do some tests on it before throwing it away? Heck, it could even be an infrared photo-diode (depending on where you removed it from) since many of these "see" through black plastic. And you won't be a noob forever. Lay it aside if you can't make sense of it...
  10. hevans1944

    Beginner question: Can I convert speed fan switch to three?

    Probably not. Most fans depend on a rotating magnetic field generated in an induction motor, speed of rotation depending on pole winding configuration and power line frequency. OTOH, if the fan has brushes and operates on DC as well as AC (uses a universal motor), a light dimmer or a variac...
  11. hevans1944

    PWM solenoid use

    This looks doable. It also appears that you are not a total stranger to electronics, given you have already considered using an Arduino board with a quad totem-pole switch, the L293. I, OTOH, know very little about automatic transmissions... Other than what I learned by watching the video...
  12. hevans1944

    60 watts to 50 watts

    Thank you for the kind words. IMHO Colin can sometimes be a little cryptic, but his comments are usually spot-on if you put forth some thought and effort.
  13. hevans1944

    60 watts to 50 watts

    And it could probably be hacked to provide closed-loop temperature control too, since the output is adjustable with the trimpot on the board. Multilayer PCB construction with plated-through holes, appears to be quality assembly... what's not to like at that price? Just add your transformer...
  14. hevans1944

    60 watts to 50 watts

    This sounds like an ideal application for a pulse-width modulated (PWM) power source, with negative feedback from a temperature sensor (thermistor, RTD, or thermocouple) to control the final cooler temperature. Hang your bridge rectifier and filter capacitor on the transformer and build on from...
  15. hevans1944

    Looking for receptacle lube

    I have used a silicone lubricant for such things, Dow Corning Vacuum Grease, which is intended to lubricate fritted glass-to-glass rotating seals such as stop-cocks. A metal-to-metal contact pushes the lubricant aside and the lubricant seals out the entry of air. I have also used petroleum jelly...
  16. hevans1944

    8-Pin Development Board

    Were those catalog pages printed on heavy slick stock? Someone should look into making "paper" specifically for toner transfer, maybe something like the stuff they use to transfer images to T-shirts and coffee mugs. I used to see mall kiosks selling this, but no idea what they were using for...
  17. hevans1944

    Footprint

    I know almost nothing about spring delay lines, but it would appear that mounting it vertically would increase the weight load on the driver coil, which may lead to unacceptable operation. Best suggestion I can think of is to temporarily try it in a vertical orientation and see what affect that...
  18. hevans1944

    Help with a component Please?

    Your answer was posted on another forum and can be found here. It is considered bad manners to cross-post to two or more forums at once with the same question. You should wait a few days after your first post to see if there is an acceptable answer, this to avoid wasting our time here.
  19. hevans1944

    electronic apps

    I would be happy to have an Android app that reads the bar codes on my extensive collection of Blu-Ray and other DVDs and then translates that into a description I can refer to the next time I visit Second Time Around to purchase a used disk. I hate buying the same disk multiple times because I...
  20. hevans1944

    8-Pin Development Board

    Hmm. I see you remembered to mirror-image the original artwork for hot-iron transfer to your circuit board. Good job! Don't need a silkscreen if you can transfer toner "ink" from paper to board.
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