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  1. (*steve*)

    How To Interface 12v 10w Solar Panel To 12v 1.3ah Battery

    If it has a voltage regulator you can
  2. (*steve*)

    Understanding a regulator circuit with MOSFET and Zener-Diode

    Aaah, I see. I assumed that the Vgs which appears in the formula is a calculated value (possibly read from a graph). I interpreted the question to be more along the lines of why does the circuit work and why does the voltage across R1 stabilize at some particular Vgs. If the question is as...
  3. (*steve*)

    How To Interface 12v 10w Solar Panel To 12v 1.3ah Battery

    Place a 14V 20W zener across the solar panel, then connect it to the battery via a 1A diode. This should charge the battery to about the float charge voltage (check the battery specs for more details)
  4. (*steve*)

    Smd resistor unbelievable

    I suggest you check again. R83 certainly looks like it will dissipate power. 0603 resistors are commonly rated at powers like 0.063W. maybe it's R63? R93? R88? Check what the resistor is connected to.
  5. (*steve*)

    Understanding a regulator circuit with MOSFET and Zener-Diode

    But there is feedback. As the voltage across R1 increases, Q1 increases it's conductance causing R to drop more voltage, reducing the voltage across R1. D is the reference. The voltage across R1 is compared to the threshold voltage of the MOSFET which acts as an error amplifier which...
  6. (*steve*)

    Understanding a regulator circuit with MOSFET and Zener-Diode

    No, it's due to feedback.
  7. (*steve*)

    Nostalgia

    A colleague and I spent a few hours at the computer history museum just outside San Francisco. It was all "used one of those", "had one of those", "seen one of them", "ooh, always wanted one of them", "saw the advertisement", "own a piece of one of them", "wow, never thought I'd see one of...
  8. (*steve*)

    Chokes on DC power supplies?

    You would be best off sending a higher voltage to the remote location and regulating it there. How do you ship power? I'm imagining you turning up at a post office with a padded bag full of electrons.
  9. (*steve*)

    What Is List In Program

    Wait, wait, lmgtfy.
  10. (*steve*)

    Led pinspot 2

    Ok, post some photos for us. Do you know what to look for in a bad capacitor? Domed tops are one indication, however they can fall without visible damage.
  11. (*steve*)

    Help to fix HP5308A counter

    There are several options, and they are all worth considering. The various options will all vary in cost, short term, and long term stability. Short term stability generally included changes in frequency due to temperature, noise in the signal, and short term fluctuations. This would affect...
  12. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    I have a solar hot water system almost exactly as you describe excerpt it doesn't have a reflector (it has 20 tubes, each about a metre in length). It wasn't particularly cheap, but it saves me about $100 a month in gas charges (and that's natural gas, not petroleum)
  13. (*steve*)

    MFOS VCO fault

    That would be ideal :-)
  14. (*steve*)

    Help to fix HP5308A counter

    First thing to check is that there's not an internal/external switch for the 10MHz signal that is in the wrong position. Next thing is to provide an external 10MHz, if that is possible, to check the operation of everything else. If you confirm that it's the 10MHz signal alone, then there are...
  15. (*steve*)

    Battery life calculation.

    It seems right. Everyone, it seems has their preferred approach in calculating this. I would calculate average current in amps and multiply it by the number of hours. Average current = (3/60 * 2e-3) + (57/60 * 2e-6) = 1.019e-4 amps Hours = 24*365 = 8760 So Ah = 1.019e-4 * 8760 = 0.8926...
  16. (*steve*)

    Battery life calculation.

    Over a year you might also need to consider self-discharge. Another issue that falls in your favour is that most batteries have measured capacity based on a 20 hour discharge. You will be discharging at a much lower rate and that will result in a larger useable capacity.
  17. (*steve*)

    How To Find Internal Short

    I'm not able to review the pictures at the moment, but if that is confirmed it is a great indication that power was applied incorrectly. It is also a reasonable indication that the device has been protected. You need to remove that diode, test it out of circuit, and replace it, before...
  18. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    You need at least one reading at close to midday with a clear sky with the sun casting light normal to the front surface of the panel.. However, it is possible that the specifications of your solar panel are a little exaggerated, or even that your 270Ω resistors are a lower value. Do you have...
  19. (*steve*)

    Real Solder

    I'll start using lead free solder regularly when I can buy a lead free lead acid battery (and I don't mean a surface mount one :D)
  20. (*steve*)

    Led driver

    Paper? What are you talking about?
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