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  1. BobK

    induction...

    Oh, it is motor control, I missed that somehow. Bob
  2. BobK

    induction...

    What is it you are trying to do? If you supplying a PWM to a coil with a flyback diode across you basically have build a buck-boost converter with a shorted output. Bob
  3. BobK

    induction...

    The current in a flyback diode will initially be the same as the current in the inductor at the time it is turned off. It will then decrease as the energy in the inductor is dissipated. The rating of the diode must be greater than the voltage across and the current in the inductor. Bob
  4. BobK

    Keypad interfacing to PIC contoller

    No, the problem is electrical and I told you how to solve it. Bob
  5. BobK

    12v LED resistors

    Yes, try the 10A range first. Then if is below 1A, use the mA range to get a better reading. Bob
  6. BobK

    2n3055 saturation

    The short answer is no. You would need a gain of 20 to get 30A collector current with 1.5A base current, and that is not likely at 15A current each, since the datasheet says it falls to 5 at 10A collector current. Bob
  7. BobK

    Possible to have safe low density infrared leds in board?

    So you mean warming as in feeling heat, not "warm" light? If this is the case, you would need 100s of Watts to actually feel the heat throughout the room. Bob
  8. BobK

    Possible to have safe low density infrared leds in board?

    Adding infrared will not change the visible quality of room lighting since you cannot see it! To make LED lighting more like incandescent, you would add yellow. Bob
  9. BobK

    Powering 5050 RGB LEDs from an arduino

    I am not sure I understand what you are asking. If a circuit has a Vin coming from the Arduino, you will use an output pin on the Arduino. Is that what you are asking? Bob
  10. BobK

    Powering 5050 RGB LEDs from an arduino

    And if they were transistors with the pinout you described, the collector and emitter are reversed. The emitter should be at ground and the collector connected to the R, G and B lines. Check out this resource on using transistors as switches...
  11. BobK

    looking for a spice model for the L293 driver

    Yes, in the direction of Google. Bob
  12. BobK

    Correct voltage translator

    Your calculation is incorrect. 6000 RPM x 3600 = 21,600,000 pulse per minute or 360000 pulses per second. Are you sure it puts out 3600 pulses per revolution? I can't even imagine how that is done. Bob
  13. BobK

    Keypad interfacing to PIC contoller

    Bad design. First of all, pushing two buttons in the same column will short a low output to a high output. But the problem you are seeing is because the input are floating when no button is pressed. You need a pullup resistor on each column. Then you need to change the row scanning to make...
  14. BobK

    from 5V battery to AC circuit with good frequency

    What frequency? What waveform? What voltage? What current? Bob
  15. BobK

    Electro Magnetic field biological effects - AC vs DC, current vs voltage?

    The most harmful electromagnetic radiation you will be exposed to comes from the sun. Bob
  16. BobK

    Charging two separate batteries with a single power input?

    Ground loop noise normally refers to AC powered circuits. There should be no problem powering both the receiver and amplifier from the same battery. What kind of noise are you getting? Bob
  17. BobK

    i would like to see alternate part numbers for #2N3906, transistor for a cannon word processor

    Why? the 2N3906 is one of the cheapest, most widely available transistors there is. Bob
  18. BobK

    Microcontroller controlled by pushbutton for LED flashlight

    I agree that hardware debug is rarely needed, and it presents a lot of problems of it's own, such as stopping at certain points in a program can cause hardware smoke! Bob
  19. BobK

    Microcontroller controlled by pushbutton for LED flashlight

    Hop, I hope I did not mislead you. The DIP versions still do not work with in-circuit debug. You need a little board ($25) that has a special chip on it to debug. I mentioned DIPs because the board has pins to plug in to a DIP socket to replace the normal DIP chips...
  20. BobK

    Microcontroller controlled by pushbutton for LED flashlight

    The simulator is usually the way to go on the low-pin-count chips, but there is also a hardware solution. You can get a "debug header" which contains a special chip with extra pins for in-circuit real-time debugging. If you are using DIPs, you can plug these headers right into a DIP socket...
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