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  1. (*steve*)

    Swapping magjack/ethernet port on PC motherboards

    If it's just the connector (or the magnetics inside a connector with embedded magnetics) then sure, you can replace it. However, if the problem is any deeper then the task gets harder and harder. Beware that motherboards use multilayer boards and internal ground planes, so desoldering through...
  2. (*steve*)

    Swapping magjack/ethernet port on PC motherboards

    It may be more than just the jack. My recommendation would be to disable the on board Ethernet port and install a separate Ethernet card.
  3. (*steve*)

    LED light: 120V and 25watts vs 12Volts and 25 watts: whats the difference?

    I agree, the difference between energy and power is significant and somewhat akin to the difference between A and Ah. We rightfully point out where people use the latter pair incorrectly, so doing the same for the former is just bring consistent. At the time, I was going to comment to...
  4. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    Do you have a multimeter? With the charger unplugged, but the power switch turned on, use the resistance range to measure between each battery charge terminal and each power cord terminal. That will be 6 readings in total. Ensure you do not see continuity (or a low resistance) on any of these.
  5. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    You need to check if either output lead is connected to any input connection. The most likely one would be the earth connection.
  6. (*steve*)

    Holiday pics

    It's an art gallery like no other :-)
  7. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    Why do you need to separate them to use the two chargers? Do they have a common outputs connection (is one side grounded)?
  8. (*steve*)

    Hello People!

    Aaah, Pune! Say hello to Shankarshet Rd for me :-). The times I've been to Pune I've stayed near the hospital on that road (yeah, I know it's a long road -- there's probably more than one hospital in it :-D. What is your current level of skill with electronics? Feel free to ask us questions!
  9. (*steve*)

    Hello People!

    Hi Niraj, welcome to electronics point. Where in India are you? What is your interest in electronics?
  10. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    At this point, all I can tell you is that unless you have a common ground, your voltage divider scheme won't work. And if you have a common ground the series connection won't work. Perhaps you need to describe exactly what you want to do so we can suggest how you can do it rather than you...
  11. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    But in this post you show the negative ends of the batteries connected together
  12. (*steve*)

    2 grounds for 2 batteries in series monitoring circuits on 1 PCB

    If the grounds are not connected then you can't measure the battery voltages in the way you want to. You need to draw a circuit diagram embodying the concepts in both of your threads. You'll either see that it's not possible, or you'll describe it more clearly so we can understand that you're...
  13. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    You can't use a simple single switch like that to swap between a series config and one where the negatives are connected.
  14. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    If you connect all the batteries negative terminals together while charging, you had better disconnect them before you connect them in series -- unless you like pyrotechnics in your batteries. I'll try to address the other questions later.
  15. (*steve*)

    Holiday pics

    Yeah, it was a cruise, just a short 8 night trip to a few ports along the South Eastern coast of Australia. The last images (on the second post containing images are (of course) Sydney. We started and ended in Sydney, a really interesting place to spend a few days. A cruise ship makes for a...
  16. (*steve*)

    2 grounds for 2 batteries in series monitoring circuits on 1 PCB

    Consider what will happen to the bottom battery if you ground both sides of it.
  17. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    Another problem your circuit has is that the resistors at the bottom of all of your voltage dividers are in parallel. If all the voltage dividers are the same, then either pick a value 3 times as large as you need, or eliminate all but one of them. This assumes that you'll only turn on one...
  18. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    This is a suitable high side switch for a microcontroller: R1 limits the current into the base of Q2 Q1 is a P channel mosfet used to switch the load (whatever it is) D1 prevents the gate from being destroyed by too high a Vgs. This is important if the supply voltage is above 20V (the...
  19. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    The way you have that mosfet, the gate will have to be raised to 24V + the Vgs, so 28 volts or so.
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