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  1. BobK

    Dumbwaiter Logic Circuit

    Sorry, but a microcontroller IS the KISS solution. Bob
  2. BobK

    I know nothing...

    Good luck with that. About 20 hours of pedaling will get you abouy 1 hour of light. Bob
  3. BobK

    I know nothing...

    1000W LED lamp? I hope you have eye protection. Bob
  4. BobK

    i need advocates to keep my electronics working

    Why do you think that is? Is it something about everybody else, or might it be something about you? Bob
  5. BobK

    Operating 266V Motors on 230V..... Explain Please

    That is a 3-phase motor. It will not run from a US 230V line, which is single phase. Bob
  6. BobK

    TDA7297 cascade channels?

    The gain is 32 db or 40 V/V. What are you driving it from, a crystal radio? Anything that can drive a line input is more than sufficient to max out the amp. Bob
  7. BobK

    How did you start to learn programming?

    If you think learning to program is difficult now: I took a programming course in my first year of college. At that time (1970), programming was done using punched cards that you submitted to be run through the one computer that my large university (U. of Maryland) had for student use. About...
  8. BobK

    Old Resistors

    What makes you think there is 120V across the resistor? (Hint, there was not or you would be looking at the ashes of a resistor.) And even then, your calculation produced the current through the resistor, not the power. The equation for power is: P = V^2 / R Which comes to 5333 Watts...
  9. BobK

    Reversing polarity

    Yes, you can do it. Just look for a wire that is only activated in the forward direction, and insert the forward limit switch in that wire, then do the same for reverse. Bob
  10. BobK

    What polarity is this?

    That assumes there is a battery, which is unlikely in a powered PC speaker. Bob
  11. BobK

    Forgive my ignorance...

    Hopefully you realize that the part you linked to initially is very difficult to work with unless you have reflow soldering capability. If you are not in that realm, I would suggest T0220 type MOSFETs. Bob
  12. BobK

    Circuit Help

    It gives you 150 to 210pF Actually, the 60pF will have a lower limit, so, not down to 150. Bob
  13. BobK

    Super capacitor phone battery

    Wow, at one charge per day, they will last 2739 years. “Son, your great, great, ... , grandfather originally owned this supercapacitor.” “But, dad, it’s only 2 megawatt hours, what good is that? Bob
  14. BobK

    LED for electric heater (UK)

    You can, but it will not tell you whether the coffee maker is turned on or not. It will tell you whether you have mains power, though. Bob
  15. BobK

    Why does a dc motor "stutter"

    Does it run continuously when not loaded? If not it likely is a stepper, or a brushless DC motor that requires external electronics to run it. A picture might be useful. Bob
  16. BobK

    Super capacitor phone battery

    However, in labs, they have achieved density similar to lithium batteries using graphene supercapacitors. Somewhere in the next 5-15 years I expect to see supercaps start replacing batteries, just not yet. Bob
  17. BobK

    FYI . . . . .circa 1948

    And Just 77 years later:
  18. BobK

    Super capacitor phone battery

    This is true of some supercapacitor, but others have extremely low ESR and very fast charge and discharge rates. There are products out there that use supercapacitors to start a car, providing up to 200A for a few seconds. Bob
  19. BobK

    variable voltage reduction

    Tell us why you need this, including what is connected to the output. If this is just a signal, not intended to deliver much current, you just need a voltage divider. Bob
  20. BobK

    Hartung amplifier project

    The black dot is the input. The unconnected wires from the transformer are The filament winding, and, presumably connects to the filament of the tube, which is not shown. Bob
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