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  1. MP1

    DTMF

    I have posted a snippet of a design with the 8870. Once a valid tone has been detected (after 40mS) the STD output (pin 15) goes high and the 4-bit digit data (representing 0-9 and A-F) is presented on the output pins (pins 11-14). The STD output will remain high while the tone is still present...
  2. MP1

    LM317 Variable power supply

    Yes, as ante has pointed out, if you have a floating supply, you can simply reverse the leads of the output. MP
  3. MP1

    3-Axis Stepper Controller

    Can you post the schematic? Or did you use the one in the projects section for this chip? MP
  4. MP1

    atx power supply for robot

    I did not know you would need this much current from the 24 VDC rail. The current MAX of this chip is much lower. It does not sound like you will be able to use it. Too bad. It would have been a nice easy solution. MP
  5. MP1

    Electronic Stethoscope

    Emad, this is not directed at you... Here is what I posted in April: http://www.electronics-lab.com/forum/index.php?board=2;action=display;threadid=620 If you cannot put forth enough effort to build a project, your corrections will fall on deaf ears. On the other hand, if you build a project...
  6. MP1

    3-Axis Stepper Controller

    It is normal for steppers to run warm/hot. You will notice that the motor, when it is not moving, is in a locked position. Otherwise it would not be very good at holding a step. MP
  7. MP1

    Electronic Stethoscope

    I do not care about what is posted on another website. You seem to think you have some authority here. Build your circuit and it can be posted in the projects section. BTW: You did not answer my last question. You keep changing the course of your own stream. MP
  8. MP1

    pwm in stepper

    Kumar, Your stepper should always have the same pulse width on the pulses sent to it. What circuit are you using to run this stepper? There is a delay in between each of the motor pulses. You add to the delay time in between the steps to slow the motor down. It is hard to explain how without...
  9. MP1

    Electronic Stethoscope

    so then you are saying your theoretic changes (named thus because you have not built the circuit) are for product improvement and not to make the circuit functional? MP
  10. MP1

    need help in fm transmitter

    keile, Is this what you are building? MP
  11. MP1

    Electronic Stethoscope

    Emad, someone else posted the same fix. The other post also claimed that the circuit will work with the -9v change. This circuit "as is" is obviously highly dependent upon the microphone and the earphone used. It is also highly dependent upon shielding your cables well. MP
  12. MP1

    LM317 Variable power supply

    You cannot just flip the input to get a negative voltage if you are using a regulator. You will need a positive regulator for the positive voltage and a negative regulator for the negative voltage. I hope I did not misunderstand what you meant. If you mean a switch to use the same AC voltage off...
  13. MP1

    Electronic Stethoscope

    Emad, are these changes you made to the original schematic which is posted in our projects section? I am a little confused with all of audiogurus theory comments in here. Thank you for the update. MP
  14. MP1

    Voice-Activated Door Opener

    This link might be of interest. http://www.wrighthobbies.net/examples/speakjet.htm MP
  15. MP1

    atx power supply for robot

    Kumar and Ante, You might use a DC-DC converter chip to turn the 12 VDC to 24 VDC so that you can use the ATX power supply without adding another supply. Here is an example from the ICL7660 data sheet from Intersil. MP
  16. MP1

    MosFet

    ante, you might also try to post in John's yahoo group. "freedatasheets" as well. Perhaps someone on that group has it. MP
  17. MP1

    Bad 7912's

    Kevin, here is the pin out in case you do not have it. MP
  18. MP1

    Variable Freq Drive

    Look at your spec sheets. How much current does the IGBT require? Without looking, I doubt that your micro is going to have enough current output to do this. When you drive one device with another, it is wise to always look at the spec sheet. In some cases, the mismatch can cause a melt down. MP
  19. MP1

    Ripple Rejection DC power supply

    How are you rectifying this voltage? Post a schematic. MP
  20. MP1

    Great Free Book -

    Even the different schematic editors will have some differences in the symbols that they use for the same package sometimes. Can you post the schematic or the symbol? Perhaps recreate the symbol in microsoft paint and post the image. There are many members here who can steer you in the right...
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