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  1. bahstrike

    Joining w/ external GND killing my PSU?

    Hi all, I have a device that outputs a regulated +12, -12, +5v  supply for it's own use. The current design ties GND to the center-tap of the transformer. This device detects a low voltage DC signal from an external source. To provide a common reference, I tie my GND to external source's GND ...
  2. bahstrike

    failed RS-232 level converter :(

    I have a circuit that already provides +12 and -12 volt supplies. The microcontroller Vdd is 3.3v. I tried designing a transistor / resistor system to handle the invert and voltage shifts, without using a MAX232, but unfortunately it does not work..  It overheats and I could only salvage the...
  3. bahstrike

    simple voltage detect - wide range

    I'm trying to simply detect the presence of a voltage,  either AC or DC,  across a wide range  (5v through 240v). I attached a picture of my current schematic.  LTV817 opto-isolator gain should be around x10. However I think I can simplify this design to fewer resistors and relays. Range...
  4. bahstrike

    dual-output transformer

    I have a 12VA CT transformer,  from which I would like to get both  24vdc and 12vdc. As shown, I use Top-Center to get 12v,  and  Top-Bottom  to get 24v. The transformer is rated for  500 mA @ 24v series output,  and  1 A  @ 12v  parallel output. I expect to simultaneously draw maximum  35mA ...
  5. bahstrike

    digital x-ray

    although i consider you guys to be the masters here, seeing as it's an electrical engineering website..  i still want to toot my programming horn! please check out the video for a 1-minute demonstration of instant digital x-ray.  i have reasonable understanding of the internals of the devices...
  6. bahstrike

    where i work (pic)

    log in to see pictures of my office!  the software seen is my first ever C# project,  although i've got plenty of C++ experience (among other..) the xray on screen is of my own right hand, but from a few months ago.  the X-CELL unit (in picture) is a real xray machine but it is usually not...
  7. bahstrike

    ethernet portal circuit

    i am ALMOST done with this, still need a voltage regulator or maybe some level shifters depending on what is chosen for SPI master.. the key to keeping it DIY-able  (imo, but im a lousy engineer) is finding a jack with built-in magnetics.  i have tried to use (even make) transformers in the...
  8. bahstrike

    attempting 44.1khz 16-bit digital audio

    hi all, i dont know much about audio circuit design, but i am attempting to make a basic stand-alone digital speaker to be connected to a larger system. the speaker itself needs no indicators or knobs/buttons:  only receives audio data and few simple commands (such as volume control).  the...
  9. bahstrike

    First SMT board: a 5-day photo adventure!

    This was my first ever attempt at surface-mount soldering!  8) Each post represents 1 day in the process and includes one or more photos (log in to view). Shown is the progress from Parts to Product.  ;D DAY 1: Received parts from Digikey
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