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  1. MP1

    Electronic Stethoscope

    There are problems with that analogy. You are missing the point and becoming argumentive. I am not going to waste my time arguing with you about this simple amplification circuit. As with my other post, if you have something to offer here, then build it. If all you have is theory, put it in the...
  2. MP1

    LC Metre

    kyriakos, what changes were needed in the schematic? Since you tested the circuit with several different display types, it would seem that the code is not correct for 4 bit display communication. Had you not tried other display types. my first guess would have been that you have one of those...
  3. MP1

    About Projects Q/A

    This area speaks of projects. If you build a project and find mistakes, please let us know the corrections so that changes can be made to the original. If you just want to theorize what might be wrong or what does not work, I think that is a subject for the theory articles area of the community...
  4. MP1

    Electronic Stethoscope

    audioguru: I would have built this dofferently myself. However, I would have built it, tested it, and posted it at the time. I see what you are talking about with the feedback in the schematic. I am not the author of this project and will not speculate what he meant to do. However, it should be...
  5. MP1

    Intel iSBC boards --- Plus

    I can help with links for the assembly language. http://www.programmersheaven.com/zone5/cat709/15567.htm http://www.bipom.com/xasm.htm http://www.eunet.bg/simtel.net/msdos/asmutl-pre.html ...and perhaps a disassembler? http://freespace.virgin.net/roger.spriggs/digital.htm MP
  6. MP1

    Electronic Stethoscope

    what are you talking about with 2 of the op amps running open loop? I am looking at this circuit to see what problems you have noted. MP
  7. MP1

    Reading Circuit Schematics

    Here is one: http://www.learn-c.com/schemat.htm MP
  8. MP1

    Electronic Stethoscope

    CDAK, thanks for coming back with a scope diagram. It is not really all that bad. A scope will make things look ugly when they are not perfect. Does your circuit have a little better looking signal when not amplified as much? You might be able to clean this up a bit with an expandor circuit...
  9. MP1

    H-Bridge

    From your description, it sounds as if you do not have enough current to your H bridge circuit. Check out this link for more on H bridge circuits. However, you might be able to just increase the current available to your present circuit and make it work...
  10. MP1

    HO Scale Slot Car Racing Tree

    Hey, I just came across this schematic. Reminded me of yours. The author's name is Bill Bowden. I will give him credit here. His article reads: The LED traffic Light circuit controls 6 LEDs (red, yellow and green) or both north/south directions and east/west directions. The timing sequence is...
  11. MP1

    4N25 Schematic check

    Now where in my post did you read me to mean the diode was in series? Yes, if you have a fan with this protection, it is parallel, but no it will not blow anything up. Your power supply can handle this. The diode protection and current limiting in the power supply will pull the current down to...
  12. MP1

    HO Scale Slot Car Racing Tree

    If I understand the circuit correctly, the 555 is starting the count and the 4017 is counting so that the different lights come on in a sequence. Therefore I would trigger the 555 for a restart or to stop the circuit. Have you thought about using a microprocessor to control this circuit? You...
  13. MP1

    sms transmitter

    Perhaps this will give you a start: http://www.funsms.net/sms_tutorial.htm MP
  14. MP1

    4N25 Schematic check

    Some computer fans do have the diode built into them. If you can reverse the direction of the motor by switching the wires, then it does not. If you can switch the polarity of the wires and it will not run, then there is a diode built into the fan. MP
  15. MP1

    MT8888 can't dial. Why ?

    You must send the AT command to pick up the line before the phone will dial out. Otherwise the DTMF tones are not going anywhere. Could this be the problem? MP
  16. MP1

    temperature controller in the hatchery

    Here are some links that might get you started. http://www.myplace.nu/avr/thermo/ http://electronickits.com/kit/complete/meas/ck108sc.pdf http://www.discovercircuits.com/T/temp-cont.htm MP
  17. MP1

    HO Scale Slot Car Racing Tree

    I think you are on the right track about the light sensing sensors. When the object breaks the beam it can trigger a circuit. If you use two such circuits, and connect them together such as an AND gate, you will eliminate false triggering because both would have to be activated in order to start...
  18. MP1

    temperature controller in the hatchery

    There are a lot of methods for temperature control. Surely you have something in mind already. How did you want to go about this? Let us know something about the hatchery and the temperatures you need. I assume it is only for heat and there is no need for cooling? What is the source of the heat...
  19. MP1

    regulators

    The regulator is not changing the voltage at this end. It is already regulated. Larger caps on the output of the regulator will help curb fluctuations in voltage caused by the circuit that is being powered much better than small ones. In many circuits, I see both a small and a large cap in...
  20. MP1

    4N25 Schematic check

    You will have the same EMF effect when the motors for the fan come on like what you have when the coil of the relay is energized. It is a good plan for all motor type circuits. You would not see a difference in the way your circuit operates. It is for protection, like adding a fuse. MP
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