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  1. BobK

    Core of an electromagnet?

    Electrician, at least in the U.S. is someone who works with residential or industrial electrical power, not electronic circuits. Bob
  2. BobK

    Only one LEDs light up

    I assume you are talking about the 3 green LEDs. The two outer ones have their 2 leads connected together, so, of course, they will not light up! Bob
  3. BobK

    Building PCB from schematic

    Hi all, I have finished my project log for building a professionally made PCB as stated in Steve's stcky in this forum. https://www.electronicspoint.com/build-device-schematic-production-pc-board-t257051.html If you read through it you will see that I received (unexpectedly) 4 boards...
  4. BobK

    Bluetooth Power Supply.

    You won't find a 5V Li Ion battery. You will find 7.2V You could use a 5V regulator with that to supply power for your amp. The battery will have a power rating, in mAH (milliamp hours). For example 2000mAH. You divide the current drawn from the battery into the capacity to get the number...
  5. BobK

    Square waveform or pulse waveforms DC or AC?

    Try twiddling with the trigger level knob. Bob
  6. BobK

    My first 24 hours with Kicad.

    Creating user interfaces is a different (my cynical side says mutually exclusive) skill from software development. Bob
  7. BobK

    Overloading an output , blows transistors why?

    No. If the output is going through a transistor, like the pass transistor in a power supply, or the output transistor in an audio amp, then ALL of the current going through the load also goes through the output transitor. Too much current through it can blowit. Bo
  8. BobK

    dual rail supply and ground

    John, I wasn't questioning what you said, I was questioning the correctness of the schematic. Bob
  9. BobK

    Big Mouth Billy Bass

    Timescale. There is a lot to learn to make this project. If you were well-versed in microcontrollers and programming it would not be a stretch. bob
  10. BobK

    LED Drivers?

    Low power LEDs tend to use a resitors only. High power LEDs tend to use a constant current source. Some flashlights actually use a boost converter and can provide full power even as the batteries run down. Bob
  11. BobK

    Newbie 1st Post - Soldering Iron Advice

    I've been doing electronics for over 40 years, and I have never had a soldering iron as fancy as that one. I use a 30W iron with a simple temp control that is not really a temp, but a power control. Edited: Here is a link to the one I use. I lied, it is actaully 40W...
  12. BobK

    dual rail supply and ground

    Shouldn't the capacitors C1-C8 all be connected to ground where they cross? The schematic does not show them connected. Bob
  13. BobK

    Amplifier for unknown loudspeakers?

    Yes, that is the kind of thing I was talking about. Bob
  14. BobK

    RF choke on a video camera--will it remove mains hum?

    Or maybe it will have a better circuit that does not pick up hum. Bob
  15. BobK

    Does chocolate work as thermal paste?

    Not to mention mustard, but that makes sense as it is traditionally used on hot dogs. Bob
  16. BobK

    Big Mouth Billy Bass

    I think this is a bit of a stretch. Bob
  17. BobK

    Amplifier for unknown loudspeakers?

    You can get complete boards for less than that. Try Ebay. It does not have to be exactly 2W. A higher wattage will not hurt anything as long as you do not turn it up too high. Bob
  18. BobK

    Resistance wire question (nichrome)

    You could try plating silver onto them. Bob
  19. BobK

    HCH-1000 Humidty Sensor

    The frequency varies with humidity. The micro could count cycles over a fixed period, say 1 second then perform some math to get the humidity. Bob
  20. BobK

    Resistance wire question (nichrome)

    You could twist the nichrome wire with some copper wire ending the copper just before the point. Bob
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