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  1. hevans1944

    200vdc 1A supply, adjustable 180-220vdc

    Well, as long as you don't adopt my long-winded style I think we'll be okay. And there is the Off-Topic Members Lounge where almost anything is okay. But, back on-topic: If I can clear the junk off my electronics workbench in the basement and find some "spare time" I will breadboard a circuit...
  2. hevans1944

    Soldering Connections For My Replacement 3.5 Stereo Plug

    Well, since you don't have one yet, why not study for an amateur radio license? No code required in any country of the world. I am sure there are some hams in Great Britain that would "Elmer" for you. The crimp tubes sound like they might work. Here on the other side of the pond I can buy...
  3. hevans1944

    Sensor for solar irradiance

    As you have noticed, laboratory-grade solar irradiance measurements tend toward the expensive. For your purposes you would like to capture the Sun's energy output at your location, over its entire spectrum that makes it through the atmosphere, from the near-ultraviolet to the far infrared. All...
  4. hevans1944

    Capacitors of different capacity in series

    So, do you mean you have charged the 2 μF capacitor to a potential of 2000 V between its two terminals, and you have also separately charged the 470 nF (0.47 μF) capacitor to 1000 V between its two terminals, and then you have connected the two capacitors in series? Let us assume this is so. If...
  5. hevans1944

    200vdc 1A supply, adjustable 180-220vdc

    Yep, H. Evans it is. Born Sunday, June 25, 1944 at high-noon local time in Welch WVA. More information available if you Google my amateur radio call sign: AC8NS.
  6. hevans1944

    New to electronics

    Thanks, John. I wish I had this kit sixty years ago, but most of the components (except for resistors and capacitors) didn't exist then. I really would have appreciated the solderless breadboards, but we had to make our own back then out of two brown particle-boards with a prepunched array of...
  7. hevans1944

    For Sale: Box of IC, parts, components for sale

    Yeah, and it's always nice to know the seller's address when attempting to purchase something.
  8. hevans1944

    Soldering Connections For My Replacement 3.5 Stereo Plug

    What your image shows is tinsel wire. This cannot be successfully soldered. A mechanical crimp connection is required. Good luck finding a plug and a crimping tool for that.
  9. hevans1944

    Capacitors of different capacity in series

    Substitution of 0.47 μF = 470 nF yields a series value of 0.3806 μF = 380.6 nF.
  10. hevans1944

    For Sale: Box of IC, parts, components for sale

    Hmm. Could "08536 area code" actually be a ZIP code for Plainsboro, New Jersey, USA? That's a long drive from Dayton, Ohio.
  11. hevans1944

    200vdc 1A supply, adjustable 180-220vdc

    Herman, I have been there, had to do that. I got started in electronics in Morristown, Tennessee, about 1953 or thereabouts. This wasn't exactly a rural town, but it was close. I walked to school, and sometimes helped feed a pig after school. The pig was being raised by a school chum for profit...
  12. hevans1944

    Is it possible to use a stepper motor without a micro-processor ?

    All you need to drive a stepper motor is a quadrature clock, which can be obtained from two D-type flip-flops. Add some transistor drivers for the motor coils and a clock oscillator for the flip-flops and ... Voila! Back in the day, before PWM became popular, we did this with hundred volt power...
  13. hevans1944

    Reducing amps in a circuit without change in the voltage

    Okay. Is there any continuity between "earth ground" and either the barrel or the center contact on your adapter when it is plugged into the wall outlet?
  14. hevans1944

    New to electronics

    I bought a Radio Shack Electronics Learning Lab Kit for a grandchild a couple of Christmases past. I liked it so much, I bought one for myself. IIRC it sold for about US$60 then, but RS has been liquidating stuff left and right and lot a RS stores are closed, so this kit of parts is becoming...
  15. hevans1944

    looking for feedback on feasability of this idea...

    You have one thing going for you: conversion of electricity to heat is 100% efficient. You don't need a thermistor. An ordinary resistor will convert whatever electricity is supplied to it directly into heat with 100% efficiency. Your problem will be to collect and store enough sunlight with a...
  16. hevans1944

    200vdc 1A supply, adjustable 180-220vdc

    You can build a filtered DC supply providing unregulated 230 V at 1A to a series three-terminal regulator that outputs an adjustable 180 V DC to 220 V DC. The voltage drop across the series regulator will vary from 10 V DC at 220 V DC output to 50 V DC at 180 V DC output. Worst case current of...
  17. hevans1944

    Ohm resistance controller

    Oooh! "A simple ohm resistance controller." What is that, perzactly? Can you post a schematic showing how it is used in a circuit? I have cruise control on my vehicles, but it is just a button I press after turning cruise control on by momentarily pressing an ON button. If I hold the button...
  18. hevans1944

    Reducing amps in a circuit without change in the voltage

    This appears to be a Maxine (made in India) AC-to-DC Power Adapter sold by Shah Electronics. Very little information is available on either the Maxine website or the Shah Electronics website although the latter page does provide an enticing description: STANDARD AC-DC Adaptor (Regulated)...
  19. hevans1944

    Reducing amps in a circuit without change in the voltage

    Well, if you look at the picture you posted, it pretty clearly shows the center conductor is negative while the outer conductor is positive. I have re-posted it below, so you don't have to go back and find it. Now what does this tell you, after connecting the output of this wall-wart to your...
  20. hevans1944

    Power Supplies - Common Terms and Limitations

    Here is a nice article on foldback current limiting. I hate this mode of operation and much prefer that the heat sinks be sized to allow indefinite full current output at zero voltage.
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