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  1. kellys_eye

    LED circuit contains caps, diodes, resistors, what's going on with this?

    I very much doubt the crystal body connects to Vcc and there's no way an LED would work with BOTH ENDS connected to Vcc...... neither would a capaitor be part of the arrangement as they block DC. Clearly your tracing is incorrect. What is this LED? As far as I understand it is a 'built-in...
  2. kellys_eye

    Generac Smart Management Module Dead

    We now have to consider WHY the bridge rectifier shorted. Whilst random failure (potentially as a result of high in-rush current) is possible, other parts downstream of the bridge rectifier could have gone short and 'taken it out'. Test Q1. If that passes then the bridge may indeed be the...
  3. kellys_eye

    Large text-based low-power display ideas

    Bog-standard 0.56" LED's (even alphanumeric) can be seen 'from a few metres' - and multi-segment LEDs can be had up to 6" in size. If power is your ultimate worry then you're only really viable course is the electro-magnetic flapper type display. On a one-off basis you should look for...
  4. kellys_eye

    High Voltage Direct Current

    There does seem to be an awakening albeit a slow one. Watching proponents of Net Zero get slaughtered by members of Congress ("Since we're spending $50 trillion on Net Zero, can you tell me by how much this will reduce global temperatures?..........." - The person answering tried to obfuscate...
  5. kellys_eye

    how to limit surge current?

    When @crutschow questioned the possibility of a connection diagram he, like I, actually exected to see one, not the description of it! Post a pic!!!
  6. kellys_eye

    Looking for advice powering 100v CRT on US 120v AC

    Yes, but it means 'nothing' in the sense of what you're trying to achieve and changes nothing about the original devices spec. As for powering it from DC - many devices have built-in SMPS circuits to develop the internal voltages which themselves may all be derived from ONE single voltage...
  7. kellys_eye

    Battery charger cable for Zonare Z-one ultrasound portable scan engine

    At those prices I'd be taking the panel off and fitting a standard connector. It's not as if this is a critical safety issue - it's clearly a manufacturers choice based on an ability to screw the customers (think Apple).
  8. kellys_eye

    High Voltage Direct Current

    True - but it doesn't have to be LEGAL tender. The paper (fiat) dollar isn't legal tender either. It's whether or not the users have FAITH (or trust) in whatever they use as a currency that makes it work. The US dollar is paper, pure and simple. Paper and ink with ZERO intrinsic value...
  9. kellys_eye

    Looking for advice powering 100v CRT on US 120v AC

    You need an auto-transformer. Some UPS devices that have line voltage monitoring/control have transformers with suitable taps that can cater for 100V in, 120V out (and 140V in, 120V out) that would do the job. Alterntively you can delve 'in' to the monitor as the 100V input is liekly converted...
  10. kellys_eye

    Has anyone ever replaced a garage door opener that uses the old fashioned dip switch decoder with a raspberry pi? I need to use the old remotes.

    There are undoubtedly existing (new) systems that offer a tx/rx solution to the problem and probably easier to take the decoded output of the 'new' system to operate the 'last part' of the existing receive/open/close system. The MC145028 has an output pin (Vt) to indicate a correctly received...
  11. kellys_eye

    Does anyone recognize this company logo?

    Is that a TNC-to-BNC adapter? Looks like the SHF version, perhaps for an oscilloscope input?
  12. kellys_eye

    High Voltage Direct Current

    Not so - there are actual currency notes that have been printed with real gold embedded in them (albeit probably an evaporated layer of it). They are called 'Goldbacks' and issued in Utah and Nevada and New Hampshire and they are accepted currency in many places there...
  13. kellys_eye

    wheelchair charger

    Just go to Amazon and search for 'sealed lead acid charger' - they will be country-specific so no real point my recommending one as I suspect ou're not UK-based as I am.
  14. kellys_eye

    wheelchair charger

    Many car battery chargers have dual functions that allow 'normal' and sealed lead-acid (the type you have) batteries to charge safely. Check the labels and there will be something that suits. Charge the batteries individually else purchase the manufacturers recommended charger.
  15. kellys_eye

    Equivalent to O6N03LA N-type mosfet

    Practically EVERY major component supplier has a PARAMETRIC SEARCH facility for components. In other words, if you know some (any) parameters of the device you seek you just click on the values listed and each 'click' reduces the list of suitale devices (from the tens of thousands to start...
  16. kellys_eye

    74LS161 driven by MX045HS

    Way past anything I'd try - 10MHz would be my limit but perhaps psuhing it to 20MHz with careful wiring (i.e. short, direct) If you plan to take your project further then a 'scope and/or analyser is a must. i.e. using a 'scope would find the issue in minutes......
  17. kellys_eye

    74LS161 driven by MX045HS

    Don't see the power/ground connections on your images (for the clock module). Is the ground common to all boards? Those prototype boards are also prone to loose connections causing all sorts of issues.
  18. kellys_eye

    Please Help Transistor Identification

    These days the major parts suppliers list semiconductors using a parametric search method - in other words you can highlight the relevant parameters (Vce, Ic, hfe etc) and the list gets shorter and shorter as you make your choice until one pops out that will fit. Note that the parameters you...
  19. kellys_eye

    74LS161 driven by MX045HS

    The LS161 is a presettable counter. What state are the preset pins?
  20. kellys_eye

    Please Help Transistor Identification

    International Rectifier (IR) are usually fully designated as IRF so IRF9523 brings up this: https://pdf1.alldatasheet.com/datasheet-pdf/view/25887/SUTEX/IRF9523.html
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