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  1. Arouse1973

    Diffrential cable and grounding

    Sorry missed replying to this bit. I was in a bit of a rush. Single ended circuits usually have a 0V reference that all the return current head towards on the way back to the source. Differential signal are referenced to each other and not a common 0V or ground if you want to use that...
  2. Arouse1973

    Inverter That Produces a Sine Wave

    Your power loss is probably due to the fact that the two bottom BJTs need a base resistor to limit the current. What you have done is the same as connecting a forward biased diode across the outputs of the PIC. Also if you have two more PWM ports then it is more efficient to use PNP...
  3. Arouse1973

    Diffrential cable and grounding

    Ok maybe not needing a ground isn't quite right how I have explaned it. Current must travel in a loop. The sender must have the same current come back to it. So that's why opto isolaters work. The sender transmits current out and it returns. The other side takes current from its supply and it...
  4. Arouse1973

    Diffrential cable and grounding

    Don't get so hung up on ground and common. If you have two voltages with different levels then you have current between the two points. Ground is used as a referance for signals in a circuit so they return their return current to a common point. So when say you try and turn a transistor on you...
  5. Arouse1973

    Diffrential cable and grounding

    HDMI data is differential pairs and has a + and - signal and doesn't need a ground to work properly. The ground is probably used for the I^2C data and clock lines for DDC. And also for the shields that prevent noise on the data lines. You can also get fibre Optic HDMI interfaces to remove earth...
  6. Arouse1973

    Can anyone tell me what this is called?

    Looks like a transformer to me. Probably a SMPS type. Adam
  7. Arouse1973

    Sound Level Meter

    You may need a capacitor and bleed resistor on the output. If the sound changes quickly then the voltmeter might not be fast enough to capture it. thanks Adam
  8. Arouse1973

    Why do battery charger need float charging process

    You have fast charge, Trickle charge and float charge. The battery will be fully charged after the correct amount of time after trickle charge or some people call it topping off. Constant current charge for 6 to 8 hours and trickle charge for the remaining 6 to 8 hours. As I mentioned float...
  9. Arouse1973

    Op-amps and transistors for audio

    Cheers Harald Your a star. You also have a good one. Adam
  10. Arouse1973

    Purchase RC receiver transmitter

    I think you might need an opto switch or opto reflector. You would normally drive it from a pulse. And then sense the voltage level coming back, you coyld use this for telling how close you are to something. Adam
  11. Arouse1973

    Why do battery charger need float charging process

    You must not float charge li-ion batteries. Float charge is normally for LA or NIMH batteries. And is designed to prevent self discharge. Adam
  12. Arouse1973

    Mapper

    Do you mean something like this Bob? Adam
  13. Arouse1973

    Mapper

    This will work with window comparator. R6 is your connection from your jack resistor at the other end of the cable. Unit 1 R2 100K R6 1K Unit 2 R2 82K R6 820R Unit 3 R2 62K R6 620R Unit 4 R2 43K R6 430R You will need one circuit for each cable. Just an Idea. Thanks Adam
  14. Arouse1973

    Mapper

    Can you draw a circuit then Bob please. Thanks Adam
  15. Arouse1973

    Op-amps and transistors for audio

    Thanks Harald. Yes I did use 4R as the speaker resistance. I must be doing something wrong then. If you have five minutes can you simulate it as he has it and use a 4R loud speaker, including inductance as your load and see what you come up with. Strange thing is it works ok with a sine wave...
  16. Arouse1973

    Inverter That Produces a Sine Wave

    Thanks Chris Adam
  17. Arouse1973

    Mapper

    @Steve, you beat me to it! Two trains of thought are tone decoding using the NE567. And the only other thing I can think of is a several window comparators measuring the different voltages from the plugs which would form one half of the potential divider. Otherwise employ a 16 year old...
  18. Arouse1973

    Pulse

    It's called a pulse stretcher, which is what I designed for you. Adam
  19. Arouse1973

    Pulse

    This might work. Adam
  20. Arouse1973

    Mapper

    How may connection per jack do you have?
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