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  1. dave9

    The mobile power bulges

    If a bear mauls you, is it possible to continue to still try to pet its cub? Of course until the body suffers too much damage to go on. Don't. Be. Silly. And please learn english if you're going to post in an english speaking forum. It is not as though there are not forums in your native...
  2. dave9

    routing 2 channel audio to 5.1 speaker system

    ^ Or a single opamp, with the L & R inputs pulled down by resistors for faux-isolation, then opamp gain as needed. I'd not do it but it's only bass. ;) I wonder though if it's worth the bother. That Genius setup is only a 20W sub and 5W satellites and that probably at high THD. We can go...
  3. dave9

    Power and Control PC fans with Cigarette Lighter

    ^ I assume he's going to use the linked $500 Li-Ion power pack... at full throttle, 12V input, the fans are rated for 0.2A but depending on how they rate, it might be a peak and avg current is a fair bit lower, but using that #, x4 fans, say 8 hrs a night = 6.4Ah.
  4. dave9

    Power and Control PC fans with Cigarette Lighter

    I wouldn't bother with a speed controller, just pick fans with the desired airflow vs noise trade off, but if you want one, why not just use one meant for a PC to power PC fans? For example: https://www.amazon.com/icepc-Channels-Cooling-Controller-Interface/dp/B08CXYZLBK There are also some...
  5. dave9

    connector; type name?

    ^ Mostly DIY ones because they're common at hardware stores. No OEM uses these for any automobile connections I'm aware of.
  6. dave9

    What is this (Circled orange) component called? Please help

    Map out the circuit into a schematic, get the markings of the DIP14 IC above it and look at the datasheet. To me it looks like it might just be a ferrite bead. Something seems wrong, in that on a scooter you have battery and motor and this board is not built to handle substantial current, so...
  7. dave9

    Searching for a connector board

    Keyboards from laptops aren't really stand-alone, you intend to build an entire housing to put it in? The project makes no sense to me, I'd just buy a bluetooth keyboard. That's probably going to end up cheaper (not even counting the value of your labor) by the time you add housing, battery...
  8. dave9

    Remote control conversion

    Rhine makes wall switches, you should contact them and ask which works with your model of fan. http://mail.rhine-e.com.tw/en/product.html
  9. dave9

    Is it possible to repair radio ?

    Since fiddling with "the mains cable" helped, I would wonder if your power socket has weakened contacts or broke the PCB solder joints and that this power socket has an internal switch mechanism to cut in/out the batteries and it is now a high resistance. As far as anything you can check with...
  10. dave9

    Question long term storage batteries

    No, many opinions, and many topic posts that waste everyone's time are NOT good. If you refuse to follow advice and info already received, it must be because you know more than everyone else because you exercised due diligence to research and educate yourself from a battery authority such as a...
  11. dave9

    Geting Grounded

    If you are using single sided boards (a picture or link to one might help), stack two boards one on top of the other and make the bottom board a ground plane. It is an ugly way to do it, and I'd get double sided boards before doing it, but it might be the easier way towards the goal while using...
  12. dave9

    Shaky Image Samsung QLED 55" TV

    Given that it takes a while to warm up before this happens, I'd suspect a bad solder joint before a bad capacitor(s). Maybe it's on the PSU and buying a new PSU solves it.
  13. dave9

    How to Ship Optical Table

    The seller isn't willing to package and ship it for you? The main thing I would do, is insure the shipment and research whether past customers have had trouble getting the shipper to make good on the insurance claim. As far as shippers in that area, how about a google search for "freight...
  14. dave9

    How to Mount LED Display in Cabinet

    What is the cabinet material? If it is think plastic you can just cut a hole, or if thinner metal, make a bezel out of a thicker material whether aluminum, plastic, etc, and then finish this bezel as you desire. Take your time making the cutout for the LED display so it is a very tight fit...
  15. dave9

    12vDC immersion heater connected directly to a wind turbine converter???

    I meant the turbine itself, not controller, is either the 12V version or 24V. https://www.amazon.com/stores/page/67A5B412-655D-480A-9D2C-5A9247A1D5B4?ingress=2
  16. dave9

    12vDC immersion heater connected directly to a wind turbine converter???

    Do you have the 12V or 24V version of the Pikasola? It would need to be the 12V version to directly drive the immersion heater or to then use a buck regulator circuit to drop the output from the 24V version, from 24V to 12V. Since it has a controller in series you should then be fine to...
  17. dave9

    Power Adapter Variance

    It appears to be a SLA (sealed lead acid) battery unit, so for them to spec an 12vDC 500mA, it has to mean an unregulated PSU that has a low load float voltage around 15V, so there is nothing wrong with the measurement of the PSU you have. This all means that PSU should work but you cannot use...
  18. dave9

    Creating a 9VDC adaptor for my multimeter.

    It seems like a serious of bad choices, especially if paying that premium for batteries. How about a new meter that takes 2 x AA cells then use the same LSD rechargeable AA NiMH that you can make use of in other devices? Or even alkaline, in the case of AA I still find them useful for slow...
  19. dave9

    A really small and cheap audio stereo amplifier 3w/3w from 5V psu

    For what application, general purpose music listening? I'd think a better target for a class D battery powered amp is 12V, powered by a cordless tool battery or 3 x 18650. What battery arrangement is a good match for 5V, max 5.5V anyway? PAM8403, even within the use of a 4ohm speaker to get...
  20. dave9

    Amplifying speaker without amp or power supply

    What is the rating of your POE power supply, and how much of that is the phone using, besides driving the speaker? That's your power budget, but you will probably need a buck regulating supply to trade volts for amps, maybe shoot for around 12V out to a class D amp circuit. You'd take the...
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