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  1. BobK

    Op Amp Circuit Noise

    You cannot use a voltage divider that way because the load is part of the voltage divider. You need a regulator to drop the voltage. Also, what is the reason for running them at lower voltage? Bob
  2. BobK

    detecting battery charge level

    Is the battery going directly to the Vdd supply of the micro or are you going through a regulator first? Bob
  3. BobK

    Need to replace DC gearmotor with a stepper one

    You do not need a stepper with the equivalent torque, you would gear it down (just like the original motor was) to achieve the needed torque. Bob
  4. BobK

    PIC16F877, 250Hz PWM

    Then I guess you should just give up. Seriously, though: If the pulses are all on increments of 50uS you can set an interrupt to occur every 50uS and decide what needs to be done at each interrupt. This would be less complicated, but more overhead. How much of the processor time is needed...
  5. BobK

    Hook Up Wire for PSU

    Quality, cost, or time to market, pick any two. Bob
  6. BobK

    detecting battery charge level

    Don't know if this is possible with Arduino, but here is a good trick to do this on PICs. PICs have an internal precision reference, which is settable to 1.024, 2.048 or 4.096V. You can measure this voltage with the A/D using the battery voltage as the reference for the A/D. From that you...
  7. BobK

    5Volts Signal to 60V

    So you did not want a 60V signal (meaning low current) out, you want to switch the 60V supply to the motor, right? If so, this is a different problem. Bob
  8. BobK

    PIC16F877, 250Hz PWM

    Then you need to use interrupts. Determine when each pulse starts and stops and use the timer to interrupt at those times and toggle the outputs. Bob
  9. BobK

    PIC16F877, 250Hz PWM

    There should be no problem doing that using delays. 50uS is 250 instruction times. Bob
  10. BobK

    Pickit 2 - won't write.

    The pic shows a blank program memory. Are you sure you successfully imported it? Bob
  11. BobK

    constant current LED driver without PWM (and flicker)

    In addition to the info that PWM does no imply flicker, a constant current supply does not output a PWM waveform. It may use PWM for dimming, but if you are using that, there is no PWM. Bob
  12. BobK

    Need help to getting started

    You do not start from no knowledge and start designing circuit. You start with well-known designs. You build them, you study them, you understand what each component is doing. Eventually you start making small modifications to your basic circuits, adapting them for slightly different behavior...
  13. BobK

    Offset - Zener or Linear Regulator

    What is the reason for needing 2.5V. Normally, when using single supply opamps, one simply splits the supply voltage to give the largest headroom. Bob
  14. BobK

    Transistor hfe

    Sound to me like it is wired wrong and you have, essentially, a diode (either BE or BC) between the input and the output. Bob
  15. BobK

    Where Can I Buy a 100w Resistor?

    The bands look like brown-black-red, which is 1K and brown-black-orange, which is 10K. They are 1/2 W at most. Bob
  16. BobK

    Soldering station smoking problem?

    Okay :)
  17. BobK

    More Range From 10 turn POT

    And, as for your original problem. The range of voltage you can get with a 10K pot goes up to 105V! No wonder you use only 1 turn out of ten. Use a 1K pot, which will max out at 11.6V or a 500Ω which will max at at 6.4V. See calculator here...
  18. BobK

    More Range From 10 turn POT

    If you are trying to keep the heat to minimum, and you need a max of say 6V, you should reduce the voltage of the transformer. Using a 9V transformer instead of 16 would reduce the heat produced by almost half. Bob
  19. BobK

    Fender Strat wiring question

    As long as there is no strain on the wires, I don't see why a soldered connection should not work and last basically forever. Can you show us a picture of your soldering? Bob
  20. BobK

    Highest density RGB LED strips that aren't addressable?

    Here are some that are 120 LEDs per meter. http://www.amazon.com/s/?ie=UTF8&keywords=600+led+strips&tag=googhydr-20&index=aps&hvadid=75580132323&hvpos=1t1&hvexid=&hvnetw=g&hvrand=3868816387625333374&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_1pkvpo3xlo_b I searched for "high density LED strips"...
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