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  1. BobK

    Microcontroller output is open drain?

    Read section 26.5.6 Bob
  2. BobK

    Constant Current Source

    Yes, but it would no longer be a constant current source. Bob
  3. BobK

    Triangle wave generator

    LTspice. If is free from Linear Technologies, and works quite well. Bob
  4. BobK

    voltage regulators

    The current drawn from the input will be a little higher than the current at the output. This amount is the quiescent current specification for the regulator, and it is the current needed to operate the regulator. Bob
  5. BobK

    A question about pots

    Why would not trust the original design? I mean, how many millions have they sold, and there is no uproar that I have heard of about them overheating and dying. I would just put it back to the way it was. Bo
  6. BobK

    Could you help on interpreting part of a circuit?

    Those are Sallen Key active filters and should drop off at 12db / octave each. The capacitors without the p are in uF. 0.068 uF = 68nF or 68000pF Bob
  7. BobK

    Triangle wave generator

    Here is a circuit that simulates well anyway. V2 is the triangle wave input. If you use a microcontroller with a DAC you could output this directly, or you could use PWM with an RC filter to make a crude DAC, or you could use an external DAC. The opamp could be any single supply...
  8. BobK

    Triangle wave generator

    Basically, a voltage regulator is just a an error amp and a pass transistor. You could build this yourself with an opamp and a darlington transistor. You would feed a triangle wave from the DAC to the + input of the opamp, and feed back the output voltage at the pass transistor to the - input...
  9. BobK

    Triangle wave generator

    If you are already using a microcontroller, why not use a DAC to output a triangle wave directly? Bob
  10. BobK

    Constant Current Source

    Whatever. I try to help. You do not answer my questions. You keep ignoring my responses. Yes, I do not deal well with people like that. Bob
  11. BobK

    Constant Current Source

    A circuit that outputs a constant voltage is called either a voltage reference or a voltage regulator. Is that what you really want? Bob
  12. BobK

    Constant Current Source

    If you had read what I posted twice and Steve posted once you would understand. Bob
  13. BobK

    Constant Current Source

    You don't read very well do you? Bob
  14. BobK

    Constant Current Source

    You cannot have a constant current AND a constant voltage with a changing load. This is basic electronics (Ohms law) as I already showed you. If the load changes, the voltage must change to keep the current constant. A constant current source could be described as a circuit that varies the...
  15. BobK

    Wake Up Real Time Clock

    Don't know about AVR, but PICs have an internal watchdog timer that can wake it up from sleep. They also have a super low power wakeup using an external capactor that discharges slowly then wakes it up after it reaches some voltage limit. Check the AVR datasheets for something like these. bob
  16. BobK

    Constant Current Source

    Is what possible? Constant current sources are pretty simple. But you do need a constant reference voltage. Bob
  17. BobK

    Bar graph driver, 5-15V

    You will need to convert the 5-15V range to 0-12V You can do this with an opamp. Bob
  18. BobK

    Connecting multiple 4017's

    If you look at figure 7 of this datasheet it shows how to connect multiple 4017s to get a longer sequence counter. You will need 5 of them to get a ring of 37 outputs. You get 9 outputs from the first one, and 8 each thereaffter. http://www.doctronics.co.uk/pdf_files/4017.pdf Bob
  19. BobK

    Connecting multiple 4017's

    Edited, what I said was wrong, must think some more. bob
  20. BobK

    how to include a sensor to my circuit?

    Hi deep, and welcome to the forum. It would be easier for us to help you if you explained what you are trying to accomplish, rather that how you are trying to connect something. bob
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