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  1. dave9

    tens of years battery life ?

    I don't assume alkalines will last more than 5 years in use without leaking and even then, I don't use alkalines for any use where over 2 years is expected. Capacity calculations are meaningless compared to the device damage and hassle cleaning that up.
  2. dave9

    Where to add dimmer in ac led bulb?

    Since it is a single point, you could probably, effectively dim it 2 steps by just (switch) disconnecting 1 or 2 of the 3 circuits so only 1 or 2 of the 3 series of LEDs is powered. I mean switch them off at the input to the power circuit, not the output to the LEDs in case the circuit needs a...
  3. dave9

    Wire rating for HID headlight ballast

    Incan bulbs are more sensitive to a voltage drop because they are a direct resistance and output goes down (yet lifespan goes up remarkably) a lot with a voltage droop, but HID shouldn't have this issue, should boost and regulate output regardless of whether the input voltage is a little lower...
  4. dave9

    Powering car 5000w 500rms amplier and with xbox 360 psu

    Too little info. What is the voltage of the xbox 360 PSU? What is the acceptable input voltage range of the amp? I don't think you need "maxed" output unless you're just trying to damage the amp or speakers, rather it just needs to be loud enough to match the rest of the sound system.
  5. dave9

    Where to add dimmer in ac led bulb?

    You want something warmer than 5600K color temperature and higher CRI. Just because someone makes some junk and markets it towards the video light market, does not make it suitable for a video light. As is often the case, cheapest and easiest will yield the worst result and not by only a...
  6. dave9

    Tweaking tire inflator

    I think I understand the question, with the issue being that every time you plug the inflator into power it starts at zero and you must keep tapping the "+" button to set the target pressure to whatever you want to be the cutoff threshold. There is no standard /universal circuit to do that...
  7. dave9

    LED and Switch for circuit

    If it's a generic ~100mW LED, I would shoot for lower than 20mA for long life, but then again I don't suppose it's going to get many hours if running off a 9V battery. Just suggesting that it would be bright enough to see at 10mA for just a power indicator.
  8. dave9

    PC power supply schematics and other related info

    Thanks. Since that is just a collection from around the web, I've made an offline version with just the needed HTML and images in a zip file. 2.7MB https://mega.nz/file/6BhFkDJL#beUC95fFojEoZ0V69MIjbvnEWKXnr9_4dnc4jI-dyNg
  9. dave9

    tinning

    The question is too vague, like writing "every connection", but not mentioning whether that only means wires. If it doesn't mean wires, I never pre-tin new components. Old components, if they are scavenged/salvaged, they are already tinned from their former life in a product. New Old Stock...
  10. dave9

    USB Power Supply Contacts

    As mentioned previously, the pads are not there at all, because they were torn off and still attached to the legs of the USB socket by solder. Yes, all point you indicated with yellow are ground. It is common to mount I/O jacks with their frame to ground, for grounding purposes, and because...
  11. dave9

    Unusual Touchscreen Monitor Power Supply - Never saw before

    Can you find a picture of the original power cord, and is it just a cord or an AC/DC adapter brick on a cord? I wonder the same as Alec_t, whether the AC input socket is on the right in the picture (or elsewhere not pictured) and it has is own internal AC/DC PSU. If you take the cover off the...
  12. dave9

    USB Power Supply Contacts

    I use an x-acto knife to scrap the coating off, but you don't absolutely have to do that, if you're just aiming to get the power pins connected then there is an easier way. That C4 capacitor right behind the pads for the socket, is across the +/- power. Solder a jumper wire from the solder pad...
  13. dave9

    How to clean oxidized USB plug?

    Keep in mind that the contacts themselves are normally gold plated and that plating will be damaged by most abrasive cleaning options, and being gold, shouldn't have oxidized itself so should be more of a fluid suspension cleaning process.
  14. dave9

    Adding aux functionality to old boat radio

    It is unclear if the linked Pyle radio's RCAs are speaker outputs, or as likely, line-level out. You could turn the volume up and measure the voltage to see if it's getting much above 1VAC (line level). It does not mention it in the manual either (linked on that amazon page and below), which...
  15. dave9

    Easy Wiring Question

    You need to better describe all parameters of these circuits, for example if the doorbell has a 24VAC feed, and what this "porch light" is exactly. If you're trying to run some homemade low voltage porch light off the doorbell 24VAC transformer, with the light on you are probably pulling the...
  16. dave9

    USB Power Supply Contacts

    The guns are more for larger electrical work, like use a butcher knife to cut the steak on your plate as you eat it. Best value bet is pencil style on a temperature controlled solder station from a major brand like Weller or Hakko, which are roughly $100. You can still get by with less, there...
  17. dave9

    USB Power Supply Contacts

    If your Radio Shack iron is the cheap type that has a screw in *nail* type of tip (which uses nickel plating over a copper core), it might help a bit to file, grind, or sand either a flat or sharper point on it, as solder can erode that type of tip away to a concave surface that is difficult to...
  18. dave9

    USB Power Supply Contacts

    No you don't have to connect the shell to those ground pads. With a shielded cable it might provide longer transmission distances for data, but you're not using data. More critical was that this is the only way the socket was mechanically attached, the weak link and why it comes off fairly...
  19. dave9

    USB Power Supply Contacts

    Yes I've faced the same frustration with the multitude of barrel connector sizes, and even worse in rare cases when a manufacturer decides they're going to make positive power the outer barrel plug sleeve. At the same time, it beats having a broken connector and I can swap a different barrel...
  20. dave9

    USB Power Supply Contacts

    At first I was wondering, how the heck did that connector pull off and leave the pads intact on the PCB, but now that I look at it again, the pads look ripped completely off. SO, use an x-acto knife or similar, to scrape off the coating a few millimeters back from the edge of the torn copper...
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