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  1. hevans1944

    Trouble understanding shunt resistance for short-circuit current measurement

    Your test strategy seems very reasonable, especially the initial characterization phase. Don't forget to repeat the I-V characterization at the end of your field tests, just to confirm that none of the cells has drastically changed as a result of exposure to the environment and whatever effects...
  2. hevans1944

    Who-da Thunk?

    Thanks, Harald!
  3. hevans1944

    Request for CRT monitor schematic - ViewSonic E790

    You are probably going to have to pay for the download, but I agree it will be a difficult choice to make without a preview or at least some sort of sample or guarantee. Maybe someone here will read your post and have what you need. Give it a few weeks, or even a month or two, before giving up...
  4. hevans1944

    Heated Gloves

    Four hours with 2.5 A current is... um... lessee... 10 Ah! Buy a Li-ion with at least that much capacty.
  5. hevans1944

    Drone followers

    Don't forget to add duct tape to the list. Or, even better, duck tape. And sinks: Heat sinks, kitchen sinks, all drones need some sinks.
  6. hevans1944

    Request for CRT monitor schematic - ViewSonic E790

    Perhaps you could try looking here.
  7. hevans1944

    Drone followers

    Will you be going up and down stairs or ladders? Traveling outside over pavement, grass, crushed stone, snow or ice? How big is this drone? Perhaps your best bet is to buy a puppy and train it to follow you. Dogs are really good at that. Some maintenance required.
  8. hevans1944

    Quality testing of an electronic item

    Toner cartridges... what a can of worms. Quality will depend on a lot of factors that will be difficult or impossible to quantify, such as materials, toner composition, and workmanship. It would be expensive to obtain a large enough sample to perform statistically significant tests on...
  9. hevans1944

    Quality testing of an electronic item

    Even more subtle is you didn't tell us what it is you are trying to sell. You expect advice? Provide more information.
  10. hevans1944

    Do timers timer?

    The 555 behaves like a one-shot or monostable multivibrator when operated in the trigger mode. It's output stays low until triggered, then it goes high for a period of time and at the end of that time reverts to low until another trigger starts the timing again. You can use the 555 output to...
  11. hevans1944

    Hooking up deadbolt motor to TB6612FNG Stepper Motor Controller

    Yes, I think that would work. IIRC, there are built-in "weak" pull-up resistors on the Arduino inputs, but you might want to add external 10 kΩ pull-ups just to be sure the switches produce well-defined 0 and 1 logic levels. The inputs should be programmed as digital inputs, not analog inputs...
  12. hevans1944

    Hooking up deadbolt motor to TB6612FNG Stepper Motor Controller

    Are you applying 5 V DC to the motor wires alone in the lock mechanism, and not through the PWM controller? If so, the dead-bolt mechansim may be in a limit condition, as detected by one of the two micro-switches. You would need to reverse the polarity of the motor wires to bring the dead-bolt...
  13. hevans1944

    Brain tester.

    You can do a LOT of things with resistors and a circuit, but I am confused by your terminology. Does "6 core" mean six individual wires while "two core" means a single pair of wires? If so, the answer depends on how you want to "light up the three difrent LED's". Do these LEDs light up one at a...
  14. hevans1944

    Special Project with led and motors

    Beautiful! Excellent project, well done.
  15. hevans1944

    Trouble understanding shunt resistance for short-circuit current measurement

    A minor objection to your choice of shunt resistor. I have used this particular resistor to monitor and control the electromagnetic "focusing" current in a prototype filtered cathodic arc high-vacuum deposition chamber. The resistor you linked to is designed for measuring very large currents, on...
  16. hevans1944

    ESSL X990 Biometric Admin Password- Urgent Help

    Why not visit the ESSL website and ask for online support help?
  17. hevans1944

    NAU-7802 24-bit adc output stabilization

    You may have stepped off into the deep end of the pool. Please post a schematic diagram of your complete load-cell weighing circuit, including load-cell excitation method, load cell full-scale range, load-cell sensitivity, load-cell calibration method, load-cell model number (if available)...
  18. hevans1944

    Temperature controlled valve

    You should be able to do this with an all-analog PID controller. Many of these available off the shelf. Of course you can take a digital approach, too, using Arduino to mediate between electronic thermometer (whatever that is) and your valve(s). That's probably what I would because (1) it sounds...
  19. hevans1944

    Need help with homework

    You will learn even more if you follow Harald's advice in post #2: use what you learn from textbooks to build and test your own circuits. Start simple with just a few passive components and a multi-meter and a wall-wart for DC power. You can add a small "filament transformer" providing 6.3 V AC...
  20. hevans1944

    Mystery box

    So, Gramps, what are you gonna do with this blast from the past? Salvage the parts? Mount it in a shadow box on the living room wall? Throw it away?
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