Search results

Search Forums New Posts
  1. BobK

    PCB, Toner transfer method

    You forgot pre-sensitized positive boards. These are made by printing the PCB layout onto a trasparecy, then using this with a light box to expose the board to UV. You then develop the board in dilute NaOH and it is left with the resist wherever copper should stay. Then etch as usual. I have...
  2. BobK

    what is the different between speaker wire and power wire

    In properly blindef A/ B comparison, the differences these people “hear” disappear. Bob
  3. BobK

    PCB, Toner transfer method

    The cheapest way is to use a clothes iron. But I have never been able to get reliable results with either the iron or with a modified laminator. Bob
  4. BobK

    what is the different between speaker wire and power wire

    No, it is not complicated at, all, they don’t. Bob
  5. BobK

    SERVO POSITIONING??

    Agree with the 2 previous posters. A servo would likely not be fast enough to get the kind of kick you should for the initial recoil. Bob
  6. BobK

    Determine Power Supply Requirements for Simple Circuit

    You need a 12V supply capable of at least 120 ma. To avpid stressing it, use pne that can supply 150 ma or more. If you want to use a USB charger, ypu wpuld need a boost converter to 12V, unnecessarily complicating the project. The 5V supply would need to be capable of about 450 ma or more...
  7. BobK

    PWM setup

    Red LEDs are not 3.2 to 3.4V. The are typically 2.5V. Bob
  8. BobK

    Choosing a 32 Bit MCU

    If your customer is programming the device it makes sense for them to specify the type of processor, otherwise, not so much. I read a comparison a few months ago of pretty much all the microcontroller families which tested them for performance and power usage using the same algorithms. PICs...
  9. BobK

    Amplifier the smartphone headphone port voltage

    IR LEDs are typically around 1.5V, not 5V. Bob
  10. BobK

    How can I light a led from a scanner lamp using 1,25 V X 0.054 ma input ?

    You have 67 microwatts available. You might be able to light an LED enough to see it barely glowing in a darkened room. If you expect more than that, you ate out of luck. Bob
  11. BobK

    Powerbank battery level meter?

    All of the 5V power banks I have seen have 4 LEDs to show the state of charge. Bob
  12. BobK

    Li-ion battery pack

    Yes! I have two drills that are 9.6V run from NiCads and have replaced the cells once only to have them go bad again. I have the same idea, to convert to LiIon, but I have not got around to it yet. In my case, a 3S would probably drive it just fine, being about 1V high. They were slow and...
  13. BobK

    fluctuating magnetic field generator design

    Kind'a hard to wind a coil < 1mm in size. Bob
  14. BobK

    How to pursue processor/memory design

    Yep, that is the way it is likely to go anyway. Your interests and opportunities will evolve over time. One thing I might add. I would learn to design with FPGAs. These allow you to design processors that do not require the insane level of performance of an Intel or Arm processor all inside...
  15. BobK

    How to pursue processor/memory design

    I am retired from Intel. They design processors and memories there. Well, not so much design processors, as design the next iteration to improve the throughput and reduce the power used. The team of engineers that does this iterative design is about 1000 people. And that does not include the...
  16. BobK

    18650 Under voltage protection

    I love the teardown video where the guy opens one up and pours out a bunch of rice and a tiny battery. (Oh, we meant 2000uA hours, it’s a typo) Bob
  17. BobK

    Calculating current limit resistor value

    Why don’t you tell us what you are trying to connect the output to and what you are trying to protect against? As @kellys_eye and I have already said, if you are connecting to an input, no current limiting is needed, Bob
  18. BobK

    Calculating current limit resistor value

    You do not need either the capacitor or the resistor. If you are trying to protect against a short, 33 Ohms is not gping to do it, it would allow nearly 1 Amp of current. 3.3K would be more like it. Bob
  19. BobK

    remove led from uln2003 driver

    Without a schematic, we cannot say for sure, but, in all likelihood, they are simply connected to the outputs as indicators and serve no other purpose. Bob
  20. BobK

    Vertical ic getting Dameg every time i palce a new one

    Use a horizontal IC then. Bob
Top