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  1. CDRIVE

    Simple 555 synth idea

    That's not the issue. The jump over method was once common and I will understand it in either form. The problem arises when a conductor crosses another (that's connected) but there's no dot to indicate same. It leaves the viewer wondering if the designer forgot to jump over it or forgot the...
  2. CDRIVE

    Simple 555 synth idea

    That's because it's the free version of Tina. Many options are disabled. They're not saying you can't use it to teach yourself. You can't be a school and use this without being hit with a law suite. Chris
  3. CDRIVE

    Linear Voltage regulators

    It does need some feedback to non inverting input though. As it stands I don't think it has any hysteresis at all. If the LED is replaced with a relay this would cause serious contact chatter. Chris
  4. CDRIVE

    Linear Voltage regulators

    OK guys, I've compiled an exhaustive argument to these quotes. See insightful retort below.. Actually, as for using a 741 for the comparator circuit in question, I don't have a good argument, mediocre argument or even a feeble argument. That's different! :D Chris
  5. CDRIVE

    Linear Voltage regulators

    I would have posted that link too. I'm just curious why the author and so many others choose 741's. Chris
  6. CDRIVE

    Simple 555 synth idea

    4R is just another method of writing 4 Ohms or 4Ω. ;) Let's start with your schematics first. I've used LT Spice but I like Tina better. I can build a circuit in less that a tenth of the time it takes me in LT Spice. http://www.ti.com/tool/tina-ti If you're going to use a 100K + cap RC...
  7. CDRIVE

    Linear Voltage regulators

    Besides the fact that the 741 isn't and never has been spec'd as single ended supply compatible, they're also old and have been superseded by far better choices. The circuit concept in that link is OK but a 741?? ...Nah. I'd start with an OpAmp that's specifically designed for single ended...
  8. CDRIVE

    Simple 555 synth idea

    Dave, oddly enough this topic was started here, where the schematics were much easier to follow and coherent. Perhaps we should point him to LTSpice or Tina-TI for his schematic drawing. https://www.electronicspoint.com/building-ring-modulator-t250299.html Chris
  9. CDRIVE

    Simple 555 synth idea

    I just noticed that the collector signal is shorted to ground. I also see that you're not trying to drive the speaker directly from the mic as I thought in my last post but it's still not going to work as wired. Chris
  10. CDRIVE

    Simple 555 synth idea

    (1) When conductors cross paths on a schematic we don't know if the junction is connected unless it has a dot. (2) Your transistor has a 10K collector resistor. It will not drive a 4R, 8R or 32R speaker. A 32R speaker connected through a 450uF cap directly to the output of the 555 will drive it...
  11. CDRIVE

    Simple 555 synth idea

    Regarding your updated schematic... No. What part of it? Just about all of it. How can we make sense of it? It has dead ended lines and a host of issues to numerous to mention. I suggest that you post what you want and have a member design it for you. Chris
  12. CDRIVE

    Simple 555 synth idea

    I don't think you're going to produce much speaker audio when feeding it through a 100K resistor or Pot. That 10uF cap is also going to swamp out audio. Also, your jack isn't drawn correctly. There should be a speaker disconnect contact. Chris
  13. CDRIVE

    simple circuit won't work..

    What are the odds? When I spiced it I arbitrarily selected 20 turns on a ferrite core. ;) Chris
  14. CDRIVE

    simple circuit won't work..

    I didn't build it but it was too irresistible not to spice, which it did surprisingly well. I say surprisingly because spicing oscillators can sometimes be a royal pita. Chris
  15. CDRIVE

    simple circuit won't work..

    By using small gauge enameled wire. It's called magnet wire. Chris
  16. CDRIVE

    simple circuit won't work..

    If you quit whenever something doesn't work as expected you'll be spinning your wheels endlessly. Chris
  17. CDRIVE

    simple circuit won't work..

    If there's a connection it escapes me. Chris
  18. CDRIVE

    simple circuit won't work..

    Never mind. I found the link to the original article at the top of the page. http://www.evilmadscientist.com/2007/weekend-projects-with-bre-pettis-make-a-joule-thief/ Chris
  19. CDRIVE

    simple circuit won't work..

    I don't see any "turns" data in your post or in the link you posted. Chris
  20. CDRIVE

    simple circuit won't work..

    Actually, this is an oscillator. Similar to an Armstrong design. Chris
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