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  1. KJ6EAD

    Help! New to Electronics - Multiple LED lighting Circuit

    Did you breadboard with 12V? Would you have any problem using 8 or 9 LEDs instead of 7?
  2. KJ6EAD

    Resistors

    No problem; we've all been there.
  3. KJ6EAD

    Resistors

    Check my edited post above. Neither. The lamp will consume the rated wattage at the rated voltage. There's no need for a resistor if the voltage supplied is correct.
  4. KJ6EAD

    Resistors

    Why are you using a resistor with a lamp? The effective resistance of the lamp when powered at 12V is 65Ω but what math are you doing? You've also misused some terminology in your statements such as "reading wattage" and resistors having "current ratings" that indicate misunderstanding; some...
  5. KJ6EAD

    Need help to build police siren/LED flasher

    In the above tests, a "0" reading and on some meters a beep tone indicate a short. This is a typical failure mode for BJTs (bipolar junction transistors).
  6. KJ6EAD

    What do I have?

    It's a 110A 1000V power diode formerly made by Ixys. Here's a link to it's neighbors: http://www.ixys.com/PartSearchResults.aspx?searchStr=ds75&SearchSubmit=Go The NL may be a distributor part numbering prefix.
  7. KJ6EAD

    Component P 030 250

    If it's in series with the transformer primary as your sketch implies, it's a fuse, probably rated 250VAC 30mA. Why don't you test it with a meter? If it measures open, it's a blown fuse. If it measures short, it's a good fuse and if it measures a few Ohms, it's a PTC resettable thermal fuse.
  8. KJ6EAD

    Component P 030 250

    It looks like a MOV.
  9. KJ6EAD

    Component P 030 250

    A picture would help. Does it look like one of these? http://www.littelfuse.com/Products/Fuses/Axial%20Radial%20Thru%20hole%20Fuses/PICO%20Fuses.aspx
  10. KJ6EAD

    Need help to build police siren/LED flasher

    Here's a clear copy of the kit data sheet from the manufacturer. It looks like a typical astable multivibrator driving LEDs and triggering an audio oscillator. Post new pictures of the board when the suggested corrections are made and we'll look for any other problems...
  11. KJ6EAD

    Need help to build police siren/LED flasher

    Watch this soldering video:
  12. KJ6EAD

    Know who makes this potentiometer?

    It's a no name Chinese part which failed. Do you really want another, or would you like a good name brand replacement? (rhetorical question) Go to the Mouser or Digikey sites and familiarize yourself with Bourns and other quality brands, then go to their sites. Look for 1/8" shafts. The larger...
  13. KJ6EAD

    Negative Voltage on Breadboard with no negative voltage input

    You could use two identical surplus 5V cell phone chargers with a diode drop to reduce the voltage, two 3-cell battery holders with AA cells in them, a 9V supply with a rail splitter, a 9V supply with a resistive divider or any of a number of other methods. Try searching "virtual ground" and...
  14. KJ6EAD

    Silastic

    Try looking for the material by terms like "electronics grade silicone", "polydimethylsiloxane" or "alkoxysilane".
  15. KJ6EAD

    Are The Enviromental Wackos Responsible For This?

    I see that. :D
  16. KJ6EAD

    Ever wonder why Windows has more problems than Mac?

    This is not the answer you are looking for. (Waving hand in Jedi mind trick fashion.) APIs are inanimate objects and as such both agnostic and apolitical but the developers and users of both platforms are not, hence my reference to ideology and root.
  17. KJ6EAD

    Ever wonder why Windows has more problems than Mac?

    The difference between the two platforms is at it's root ideological. It can't be discussed for long without involving both politics and religion. ;)
  18. KJ6EAD

    Summing class A amplifier for headphones

    To summarize your requirements: 2 stereo inputs; 1 at line level and 1 at headphone level, mixed, equalized and amplified to 2 stereo outputs at headphone level. A musician's headphone amplifier/mixer similar to this would do most of what you want. Equalization would probably require a separate...
  19. KJ6EAD

    Help with electronic terminology

    I'm pretty sure that feeding a service cord through mortar or concrete without a conduit is not allowed by any electrical code. This was not your question but it seemed worth mentioning.
  20. KJ6EAD

    Your first self designed circuit that worked

    I don't remember which was first but I had one of those 75 in 1 lab type kits for a while, built some of the projects in various Forrest Mims books and then started experimenting with the Texas Instruments Complex Sound Generator IC (SN76477N). Somewhere along the way I started combining...
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