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  1. BobK

    Trunk Charger

    I am glad I asked then, because I would have assumed SLA. Lithium batteries are dangerous to build chargers for since they can explode or catch fire. What charger does the manufacturer recommend? Can you post a link to it? Also what is the voltage rating. That will tell us how many cells...
  2. BobK

    Looking for a used scope?

    I must admit, she was impressed with the size :) But instead, we bought a Chippendale Mahogany dining table that will be gorgeous in the mansion. Bob
  3. BobK

    12VDC to 3.3VDC LED Metered after resistor

    He measured the voltage across the LED at 0.45V. That is far below the typical absolute max for reverse voltage, which always seems to be 5V. How does that damage the LED? Bob
  4. BobK

    Trunk Charger

    What battery chemistry? How many cells? Bob
  5. BobK

    IOT: What new features I should include in my IOT based smart home project?

    I have known several people who worried about having left various appliances on after leaving the house. How about a special adapator you can plug the iron, toaster, space heater etc. into that one can check from one's cell phone to reassure them that they have not left something on. Bob
  6. BobK

    Blender conversion into rc car

    I think I will build an RC car with a steam engine. Does anybody know how large he water tank will have to be? Bob
  7. BobK

    12VDC to 3.3VDC LED Metered after resistor

    At 54uA? I doubt it. It is basically just a zener diode. Bob
  8. BobK

    Looking for a used scope?

    I found this at the Habitat for Humanity store. It is Humongous! Over 2 ft deep and maybe 14" x 18" on the front. And still, they needed a separate power supply (the box at the bottom of the cart). Marked $175 and labelled as "Antique Oscilloscope." It is dual trace, but only one probe...
  9. BobK

    Common collector configuraton

    If you are going to be so pedantic, you ought to rethink this statement. Bob
  10. BobK

    Arduino Ambilight Help - Question on amperage.

    Do you ever plug a 100W light bulb into the same socket as you might plug a 1500W heater? Why doesn't the light bulb blow up since the socket can obviously supply too much current? The answer is that a device uses only as much current as it needs. A power supply that can provide more current...
  11. BobK

    Working With 240v And Arduino

    You should try growing peanuts instead. Mushrooms: 1g of protein per ounce Peanuts: 7g of protein per ounce. Bob
  12. BobK

    Micro controller power calculation

    To get power, multiply the voltage by the current. So, in your example: 3V 5A = 15W 5V 3A = 15W 3V 2A = 6W A typical microcontroller uses microwatts to milliwatts of power, not as high as 1W. Can a device take 2V and 3A? Why not? That is like asking if an object 10 inches long can weight...
  13. BobK

    78L33 regulator

    Bah, the electronic gods would have smoked it if it was. Bob
  14. BobK

    Use of a Pull up resistor

    Since an input pin draws only picoamps, the voltage on the pin is the pullup voltage (i.e. the voltage drop is near zero). So a pullup connected to Vdd makes the input high by default. They are usually used when a switch will pull it low. Bob
  15. BobK

    Pokemon Go

    I live on a lake, and I get a lot of them. But the best ones are Vaporeon, which is one of 3 things that evolve from Eevees. Bob
  16. BobK

    78L33 regulator

    You never mentioned a supercapacitor before. It is the most likely the cause of your motor not running on start up. Bob
  17. BobK

    Appropriate Oscillator

    PICs internal oscillators are specced at ±2% from 0C to 60C and are better for a narrower temp range. If the temperature variation is small and you calibrate it, it will be well within the 3% requirement without a crystal. The tools / experience question, however is relevant. I would use a...
  18. BobK

    78L33 regulator

    Look again. There is a resistor between the 24V supply and the diode. Bob
  19. BobK

    Wives Say The Damnedest Things!

    The only silly thing (electronics releated) the lovely wife Morticia says, is, whenever I make something electronic: "It's not going to burn the house down, is it?" Well, maybe not entirely silly :) Bob
  20. BobK

    Pokemon Go

    Anyone else playing? I love that fact that the best thing to defeat an electric type Pokemon is a ground type! Bob
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