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  1. CDRIVE

    Simple 555 synth idea

    No, he used one LM324 Quad OpAmp and one LM555. Battery ground and signal ground are not the same. Chris
  2. CDRIVE

    Designing a transmitter circuit

    Your instructor is a sadist. Chris
  3. CDRIVE

    How to boost audio volume coming from a telephone

    He obviously discarded his copy of "How To Make Friends & Influence People". :rolleyes: Chris
  4. CDRIVE

    Designing a transmitter circuit

    What year of study are you in? Chris
  5. CDRIVE

    Designing a transmitter circuit

    It was impossible to not be intrigued by this so I tracked down the patent. After reading the description and tech data I can't help but wonder what the benefits are over conventional AM. Unless I've misinterpreted its end function it seems like an overly complicated way of synthesizing common...
  6. CDRIVE

    Simple 555 synth idea

    Bill's early schematics were conceptual. The link I posted contains a working prototype with p#s and values. ;) Chris
  7. CDRIVE

    Sweat monitor using electrodes.

    Some odd things going on here. There were two posts by Justin that are completely gone. One had a link to a YouTube vid that looked good and another with Picaxe code. Both seemingly swallowed up by cyberspace. Chris
  8. CDRIVE

    Simple 555 synth idea

    Well, I didn't spice it but I did read through the entire lengthy thread. I suggest that you do too. This is the last schematic entry that Bill made but there were about 5 more posts following it. Btw, in the end I wasn't wrong. It is a virtual ground...
  9. CDRIVE

    solar panel project( power is missing)

    I was particularly interested in the regulator. I wanted to see if its maximums were exceeded when you were testing it. Have you tested the Vreg again using your power supply to insure it didn't fail since the last time you tested it. You should test it with and without load. By the way, be...
  10. CDRIVE

    Simple 555 synth idea

    Not surprising that BM of AAC posted that. He's AAC's 555 guru. The ganged pots he shows is exactly what I was going to suggest. I'm going out now but I'll spice this later. Chris
  11. CDRIVE

    solar panel project( power is missing)

    More than happy to correct you.. There are more, but here's one very basic rule when posting questions on any type of help forum. When a responder asks a question, never reply with what you think is relevant or not relevant. It's not for you to decide. If you knew what's relevant or not...
  12. CDRIVE

    Simple 555 synth idea

    Actually, after looking at it again I think I misspoke. What I thought was a virtual gnd appears to be a common bias line for the OpAmps. Please post the link from which you found this. Chris
  13. CDRIVE

    solar panel project( power is missing)

    Maybe i missed it but I don't see a model number? Chris
  14. CDRIVE

    Simple 555 synth idea

    The bottom circuit uses a virtual ground. Unrelated to that I don't think it's a good choice if you need a spread of frequencies. Speaking of which, what are they? Chris
  15. CDRIVE

    Simple 555 synth idea

    Why not just post the link? Chris
  16. CDRIVE

    Simple 555 synth idea

    Keep in mind that Varicaps are manufactured in the pF range, but then I'm sometimes guilty of not staying current. This might, but I doubt it, be one of those times. ;) Chris Edit: Even if you could find a VC in the range you need you would run into issues because the cap sees DC during...
  17. CDRIVE

    Simple 555 synth idea

    For sure, you can't be the first person that has encountered this issue, so there must be a solution. If changing freq in steps is acceptable then switching in different values of C will change the freq while maintaining duty cycle. The problem arises when the duty cycle is changed. The freq...
  18. CDRIVE

    Simple 555 synth idea

    I'll give this some thought but I'm currently wrapped up in a program I'm writing for myself. I never seem to finish any of my own projects because I get sidetracked by other peoples projects. I mean to finish this one. ;) Meanwhile, I'm sure others have some thoughts in this regard. Chris
  19. CDRIVE

    Simple 555 synth idea

    As Dave did it in schematic CCT. 3 but keep in mind that you can't change the freq or pulse width without effecting one or the other. At least not this way. In other words, the 200K pots, R1 & R2 are not independent of each other. Chris
  20. CDRIVE

    Simple 555 synth idea

    Roger that! ;) Chris
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