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  1. AnalogKid

    WallWart conversion...

    No, it does not. Why do you think it does?
  2. AnalogKid

    WallWart conversion...

    Post #18 has 11 statements, and 9 of them are incorrect. ak
  3. AnalogKid

    WallWart conversion...

    It does not. The output impedance of your wall wart is less than 1 ohm. ak
  4. AnalogKid

    WallWart conversion...

    I wouldn't. Please post a clear image of the power connector area on the camcorder. Also, somewhere on the camera body, maybe on the bottom, there should be a sticker, plate, or molded-in text defining the input power requirements and model number. With a clear image of that we might be able...
  5. AnalogKid

    WallWart conversion...

    There are many ways to decrease the value of a voltage source, and they all fall into two categories: linear and switching. Both dissipate heat, one more than the other. With *any* linear technique, the power dissipated in the voltage reducing circuit will be, worst case, 2.88 watts. If this...
  6. AnalogKid

    WallWart conversion...

    Yes, but not well. The rating on the wallwart is its max continuous output current. Your device will draw less than this, and depending on the wallwart's internal circuit, the output voltage may vary inversely with it. The main issue is that the device current will not be constant. For...
  7. AnalogKid

    Automatic DC supply selection?

    Post #2 Shottkey diodes are a first step, but they will not give you the protection you want during change-over. There will be a point when both diodes are conducting because the output voltages of the two groups of panels is almost exactly equal. This is done on purpose when current-sharing...
  8. AnalogKid

    Need a little help understanding the way my class AB power amplifier works.

    R10, R11, and Tn3 perform as a zener diode. This replaces the diode-bias technique you are familiar with. The temperature tracking is not as good as four diodes in series mounted on the power transistor heatsink, but you can adjust the resistor values so the voltage drop across the transistor...
  9. AnalogKid

    Identify 1960's Diode Manufacturer By Logo?

    I forgot the question.
  10. AnalogKid

    Timer circuit

    A better analogy is that there is a fixed amount of total money (heat), and you get the same amount of money over 8 hours, whether you take all 400 in the first hour, wait 3 hours and take200 per hour for 2 hours and then wait another 3 hours, or take 3 per hour for 7 hours and then379 in the...
  11. AnalogKid

    Timer circuit

    The good news is that absolute maximum efficiency in a system such as this is not a critical requirement. Thus, a superfluid is superfluous. ak
  12. AnalogKid

    Timer circuit

    I mentioned that. Another real-world factor that is the flow rate through the heat exchanger, whatever it is that imparts heat to the water. The slower the flow, the more the water heats up; the more the water heats up. As the water heats, the delta-T between it and the heat source decreases...
  13. AnalogKid

    Timer circuit

    Actually, Alec is correct. It gets hotter because its average flow rate is lower, and that matters. As a physical quantity of heat, the calorie has been around since the 1820's, and for much of that time it was defined in terms of a quantity of water. If you have a large amount of water, such...
  14. AnalogKid

    Timer circuit

    Per kelly's suggestion: https://www.ebay.com/sch/i.html?_from=R40&_nkw=programmable+timer+relay&_sacat=0&_sop=15 ak
  15. AnalogKid

    Low frequency adjustable but stable oscillator

    That's not how it works. If you assume an infinitely accurate and precise crystal with zero drift/aging/whatever, and use it in a circuit where the output frequency can be modified by a pot, then the stability of the pot completely overrides the stability of the crystal. In worst case round...
  16. AnalogKid

    Low frequency adjustable but stable oscillator

    Agree. If the motor is running exactly 10% fast, that sounds like a 50 Hz motor running on 60 Hz.
  17. AnalogKid

    Low frequency adjustable but stable oscillator

    A crystal circuit with that adjustment range is not simple. Two methods that come to mind are phase-locked loop and direct digital syntheses. Since a squarewave signal is acceptable to you, a starting point might be a CD4060 oscillator/divider with 1% capacitor, a 0.1% resistor, and a trimpot...
  18. AnalogKid

    Help requested to identify common emitter, collector base bjt circuits

    I skimmed through the thread and did not see this: Back to the original post, #5 is incorrect. #5 is common collector, just like #2. There are pedantic, semantic, and qualifying issues with each statement, but I see the kind of truth table you are trying to construct. All of the subtleties...
  19. AnalogKid

    ECG circuit digram with AD620 and 741 op amp as a gain differentiator

    After 8 years, I don't think the OP is completely invested in a solution. In case anyone else is, here is one common way to do this. ak
  20. AnalogKid

    Using AC/AC wall adapter and converting to DC

    Maybe quality is a contributing factor, but a minor one. All transformer outputs decrease with load. Separate from that, and even without R25 and R26 in the circuit, the two output voltages are completely unregulated. This means that the AC ripple voltage component of the output voltage is...
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