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  1. hevans1944

    Measuring peak voltage of square wave - ATmega328p

    If these are square wave pulses of varying amplitudes but pretty much constant frequency (8 kHz), you could trigger an A/D conversion to occur a few microseconds after the leading edge of each pulse. I think the ATmega328p has the capability of triggering a single A/D conversion on the...
  2. hevans1944

    LED lighting without power source

    Yeah, a sensitive EMF meter is not just for microwave oven leakage tests. It's also a "valuable tool," used along with infrared cameras to detect paranormal activity for television production shows. Maybe you should call a producer of such shows, or at least a local TV news station. Everyone...
  3. hevans1944

    adaptor help needed

    Wow! That's spooky. Or maybe it is "spooks" trying to spy on you (not to put too paranoid a twist on it). I would leave it unplugged and locked away somewhere separate from your house. Maybe whoever plugged it in will come asking for it. You should install/change the dead-bolt locks on your...
  4. hevans1944

    adaptor help needed

    Did you actually visit the link I provided? The manufacturer promotes their converters as being suitable for Li-ion battery charging. Ha! I think some additional support circuitry might be needed. Do you have the power supply thingy to which the adapter is connected?
  5. hevans1944

    Pixel sensor of neural recording

    I suppose anything is possible in this age of nano-electronic circuitry. For forum members wishing to explore the possibilities, here is an article with background information. Are we ready yet to grow computers in a Petri dish?
  6. hevans1944

    Please recommend books on building remote controlled models

    What kind of "RF devices" do you want to learn how to make?
  7. hevans1944

    adaptor help needed

    It appears to be an AC power plug adapter, used with a Chinese switch-mode low-voltage power supply such as UE09WCP-SPC. Not much good without the power supply.
  8. hevans1944

    Please Design This PCB...

    Since this came right off the Texas Instruments web site, perhaps TI has a reference design available...
  9. hevans1944

    LED lighting without power source

    I have never seen what you describe, but it is possible that all that exposed wire could act as an antenna. And if there were a nearby source of radio frequency radiation perhaps it could be rectified and used to illuminate an LED. This is just a guess. Alternative (non-electronic, off-topic)...
  10. hevans1944

    Common anode or common cathode display?

    @IC71 : Nice photo! Unfortunately, a Digi Key as well as a Google search returned... nothing. Try my " D-size dry-cell and 100 Ω current limiter" suggestion to find the pins for each of the segments and the decimal point. Should take you all of a two minutes to find the segment LEDs, once you...
  11. hevans1944

    Common anode or common cathode display?

    I would poke and prod with a 1.5 V D-size dry-cell connected in series with a 100 Ω 1/4 W resistor. Some segment will light up and the reverse voltage applied by the dry-cell should not be enough to damage reverse-biased segments. You should then be able to determine if this is a common-anode or...
  12. hevans1944

    schmitt trigger

    Welcome to the Electronics Point forums! Please hand-sketch your op-amp circuit, take a picture of your sketch, and upload it here. Identify all the components by value and identitfy the part number of your op-amp. It helps if you assign IDs to each part, such as R1, R2, C1, etc. Active...
  13. hevans1944

    Timed Relay Connection/activation

    This appears to be excess OEM stock intended perhaps for a burglar alarm application. The price is cheaper than the shipping and handling costs, so if that's your cup of tea why not order a dozen or so to play with? You can learn a lot about "stuff" by actually "playing" with it. @CPLIPRR...
  14. hevans1944

    Need Help With Motion Sensor Controlled Strobe LED. II

    Hows about you sketch a schematic or wiring diagram of the circuit, snap a photo of the sketch, then upload the photo to this forum in your next post.
  15. hevans1944

    differential amplifier

    Whoa! Are we talking about op-amps (assumed to have almost infinite differential gain) or unity-gain differential amplifiers?
  16. hevans1944

    hello guys

    @The_Lion welcome to the forums. Eat hearty from the feast of knowledge available here!
  17. hevans1944

    Timed Relay Connection/activation

    Look here. Scroll to bottom of page.
  18. hevans1944

    Repair on Toshiba ARNI motor control board

    This is a sad situation. From where I am sitting, and reading between the lines, it appears you are being thrown to the wolves. If there are two hundred or so of these boards, there was probably a period of time when they were covered by a Toshiba warranty, and perhaps even a service contract...
  19. hevans1944

    Repair on Toshiba ARNI motor control board

    So, this "commissioning engineer" from Japan was there in 1982 when the boards were manufactured 34 years ago? And he remembers that these film capacitor "look a likes" are really two back-to-back electrolytic capacitors that happened to be required (in 1982) to create non-polarized 1 μF and 4.7...
  20. hevans1944

    Repair on Toshiba ARNI motor control board

    Those do not appear to be electrolytic capacitors. The look like tape-wrapped plastic film capacitors. The dark bar on one end refers to the outer foil part of the wrap, which would normally be connected to common. See this web page for information on this type of capacitor. BTW, these...
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