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  1. Arouse1973

    need to identify this capacitor

    It might be damaged then. The black mark may have been caused by local heating from within the device creating a hot spot. This is how they can fail. But they can also explode, but they shouldn't catch fire because a few years ago they had to change the material the coating was made of to a...
  2. Arouse1973

    need to identify this capacitor

    Kris is right. If they are designed in correctly then they should last for a long time. The mistake many people make is they think a lower rating is better. It's the opposite actually, they have a limited number full clamping cycles and the normal spikes on the mains can cause them to trigger if...
  3. Arouse1973

    need to identify this capacitor

    That's a surge suppressor (MOV) and not a capacitor. Thanks Adam
  4. Arouse1973

    Multiplying Voltage by a factor

    Trans diode Logarithmic amplifier might work. This scales down large input signals and allows you to measure them while still allowing small signal to be measured. But the output is the log of the input so you will need to convert it back in software if you need to. Adam
  5. Arouse1973

    EMI issue with USB connection

    Please can you supply another picture looking down on the whole circuit and as close as you can to get a clear picture. We really need a circuit diagram as soon as you can. Adam
  6. Arouse1973

    EMI issue with USB connection

    Not Really.
  7. Arouse1973

    EMI issue with USB connection

    Yes well if I didn't want to be an engineer I would also. But as he wants to learn then I wouldn't. Its not always about taking the easy way out. That's why we are here. Adam
  8. Arouse1973

    EMI issue with USB connection

    What's induction suction?
  9. Arouse1973

    EMI issue with USB connection

    I have to go now. I'll give this issue some thought. If it was a switching regulator then I could understand but a linear transformer is not normally an issue. But it could be your wiring, trying to run a USB connection like this on bread board is challenging at the best of times. There are...
  10. Arouse1973

    EMI issue with USB connection

    When it fails do you get a warning message from the PC or does it just disconnect and then re-connect?
  11. Arouse1973

    EMI issue with USB connection

    Sorry replied before pictures. It's a standard transformer then.
  12. Arouse1973

    EMI issue with USB connection

    Ok Good. So we now know it's the transformer. It this a switching power supply or a normal mains transformer.
  13. Arouse1973

    EMI issue with USB connection

    Yes I know I am not talking about replacing the transformer with a battery. I am talking about trying it to take out any problems that might be attributed to the transformer.
  14. Arouse1973

    EMI issue with USB connection

    Try powering it from a d.c source like a battery or power supply. If it still does it then it's not the transformer or it's connections, lets rule that out first. Post any schematic and a PCB layout diagram also so we can see what we are dealing with. Adam
  15. Arouse1973

    Op Amps - non-inverting

    Hi Jason So first thing to do is work out your gain setting resistors. So have you been told how to do this? Adam
  16. Arouse1973

    3 Simple Questions About PCBs

    That's the PCB manufactures problem.:rolleyes:
  17. Arouse1973

    3 Simple Questions About PCBs

    No probs Dan That what I use and I have had over 250,000 PCBs made over the last 20 years a nd they have been fine. Remember this is the finished hole size, so the PCB fab people will over drill to account for plating if needed. :D Adam
  18. Arouse1973

    3 Simple Questions About PCBs

    0.2mm larger than you component leg. So if your leg is 0.8mm then a 1mm will be fine. Adam
  19. Arouse1973

    Op amp power supply help

    Ok Cheers
  20. Arouse1973

    Op amp power supply help

    Yes but the circuit the OP supplied was for generating the half supply for operating on single supply which he called virtual ground. I don't think he was even aware of the inverting terminal virtual ground concept. Adam.
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