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  1. KJ6EAD

    in need of a really simple audio amplifier

    Gearhed31, what's the wattage rating and impedance of the speakers and how loud do you want to get? Do you care about tone control (equalization)? As a mechanical engineering student, you might like to do some math regarding the opening and closing of mechanical relay contacts and the movement...
  2. KJ6EAD

    12v LED Strobe Controller

    Whelen Engineering has an online flash application that may help with visualization and description of flash patterns. http://www.whelen.com/_AUTOMOTIVE/media/flash_patterns/index.htm The alternating (left/right) triple flash is a proven attention getter that's used in the classic "police...
  3. KJ6EAD

    Displays with more than 7 segments

    14 and 16 are the more common designations. 15 is just a 14 where they count the decimal point.
  4. KJ6EAD

    Led sequencer/scanner

    C1 is shown as an electrolytic capacitor and it's value is to be determined by you when you decide what frequency to run your 555 at. It and R1 are the timing components for the 555. In practice, I usually try to keep the capacitor value low enough that I can use a ceramic (non-electrolytic)...
  5. KJ6EAD

    Yamaha PS-35

    Regarding the three wires to each speaker; they may have a second driver such as a tweeter in each speaker enclosure.
  6. KJ6EAD

    MAKE Electronics Starting Over Advice

    How much does the components pack cost? I'd suggest rewriting the two shopping lists starting on pages 1 and 39 so they're a brief list with one item per line then take an inventory of your parts, checking off the items you have. Post the list of parts you still need. It may be possible and cost...
  7. KJ6EAD

    Yamaha PS-35

    Here's a link to the owner's manual. I didn't see any service manual available from Yamaha but I've seen them on ebay so I know they are published. Perhaps you can locate them through Yamaha's online member portal. I put the UK link up...
  8. KJ6EAD

    Problem with old ceiling fan

    2-26 is the right one for electrical equipment but 5-56 is a good second choice. http://www.crcindustries.com/ei/content/prodtree_ss.aspx?ID=251
  9. KJ6EAD

    Problem with old ceiling fan

    Yes, but they're all solid-shaft motors without the H337 suffix.
  10. KJ6EAD

    Problem with old ceiling fan

    There are a few fan parts suppliers online. You might ask them about this. Do your fans have run capacitors?
  11. KJ6EAD

    Need a backing to attach LEDs

    I've done some things with LEDs mounted on corrugated polypropylene sign board. You could try that but you must realize that soldering after insertion will require use of a clip on heat sink. The same would be true for most foam materials as well. You might also try a piece of foam core art board.
  12. KJ6EAD

    What's with the 'Ads By Google' all the time now?

    I'm using an android phone and see no ads. Maybe it's a browser dependent situation.
  13. KJ6EAD

    Can anyone identify these headers / connectors

    If that fails, you can go to the source. http://www.jst.com/index.html
  14. KJ6EAD

    Need a backing to attach LEDs

    The leads of LEDs are made of soft, plated copper so they won't poke through much, maybe some EVA (ethylene vinyl acetate) foam sheet. It's sold in ¼" thick sheets. You know that you can buy LEDs on flexible strips precircuited for 12 or 24 Volts don't you...
  15. KJ6EAD

    Problem with old ceiling fan

    I'm not familiar with that particular brand but it sounds like you have bad run capacitors. They would look like one of these: If that's not it, post a picture of that so-called transformer.
  16. KJ6EAD

    Vintage stereo receiver re-lamp with LEDs

    I should have been more clear when I said you have to run the LEDs in parallel. You put them in parallel legs of the circuit but each has it's own limiting resistor as in your top circuit. You can add as many resistor and two diode legs in parallel as your supply will accommodate but you...
  17. KJ6EAD

    Make square-wave sound better

    The simplest way to improve the sound is to create polyphony by applying the same control voltage to several 555 circuits then sum the outputs into an amplifier. The component value tolerances will produce enough pitch variation. You might try using 556 or 558 chips. Another variation would be...
  18. KJ6EAD

    Vintage stereo receiver re-lamp with LEDs

    It means you have to wire them in parallel because you don't have enough voltage to run them all in series at full current.
  19. KJ6EAD

    Vintage stereo receiver re-lamp with LEDs

    You don't need the blocking diode when you have LEDs in reverse parallel since they protect each other from excessive reverse voltage. If you leave it in the circuit, only one LED will light, the one on the left. I've scribbled the corrections on your schematic. You would only need the...
  20. KJ6EAD

    Electronic whack-a-mole

    If the link works, you should be able to try the game online. http://www.bobsspaceracers.com/frames/playagame.htm
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