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  1. CDRIVE

    Demodulation

    Well, the gentleman that authored those pages .... was quite thorough and it's definitely a college level (math) treatise on the subject. So what concept has you quagmired? Since college level electronics is 95% math there's not a lot of real world nuts & bolts, hands on bench time. Do you...
  2. CDRIVE

    Stepping up voltage

    I imagine you're referring to a design that comprises more than your basic 2 NPN's, 2 PNP's. Chris
  3. CDRIVE

    Help with timing curcuit

    LEDs and Phototransistors are very inexpensive. Combining the two as Set/Reset elements is usually easier to do, (both mechanically and electrically) than switches or other means. Best of all, they're fast! Chris.
  4. CDRIVE

    Stepping up voltage

    Yes and so does TTL. With high speed comes shoot-through and subsequent spikes on the supply rails. This is why good supply rail bypassing is important. On an H-Bridge it can be reduced greatly but at the expense of switching speed. Chris
  5. CDRIVE

    Demodulation

    Post the latest schematic that you're working from and we'll go through it. Chris
  6. CDRIVE

    switch between wall and battery power

    I had an error in that last schematic. After checking the specs for a typical fresh 9V alkaline battery it should have been 9.48V as opposed to 9,6V. Not a huge difference but .... Anyway, I also greatly expanded the 'X' scale (Wallwart (V)) too. Chris
  7. CDRIVE

    switch between wall and battery power

    Just a few notes about this schematic and plot. It assumes there is no bleeder resistor or voltage regulator integral to the wart. You can test for a back current path using an Ohmmeter with the (+ & -) probes connected to the wart's respective (+ & -) pins. This must be done with the wart...
  8. CDRIVE

    Demodulation

    Your question might win EP's 'Oddest Question Ever Asked' award. I'm not sure what you're asking. It only makes sense if your a student and want to know what your instructor might ask you about your project. As in: "Mr. Vick please explain the purpose of C1 to the class". So, is this the...
  9. CDRIVE

    Flashing 5watt led?

    Apparently you did something wrong. What ever you did may have damaged something permanently, or you have a bad or bridged connection. Trouble shooting time! ;) Chris
  10. CDRIVE

    How to increase 555 Timer Frequency

    Well, you're new here so allowances will be made. Now that you know how it can destroy the continuity of a thread I'm sure you'll refrain from repeating this in the future. ;) Chris
  11. CDRIVE

    switch between wall and battery power

    I'm going to post a plot for you so you can see how the battery current never back feeds to the wallwart. Also, you can reduce the Diode voltage drop considerably by using a more expensive Schottky Diode. Chris
  12. CDRIVE

    fet driver

    I took a quick peak at the data sheet. I'd say yes. Chris
  13. CDRIVE

    Replacement Capacitor

    See, it was easy.. http://www.grainger.com/Grainger/DAYTON-Motor-Run-Capacitor-2MDV1 The higher voltage rating than what you have is a bonus! Chris
  14. CDRIVE

    Replacement Capacitor

    Actually that style cap is still made. You'll find them on any SPH Cap-Start or Cap-Run motor. They can be purchased at any electrical supply house. WW. Granger and McMaster Carr are two on line sources but local sources are common. Chris
  15. CDRIVE

    Capacitors as timed circuit

    A 555 will easily work with a driver transistor to drive your load. Chris
  16. CDRIVE

    Looking for a partner to help develop concepts.

    Welcome to the forum and please be prepared for a verbal assault. Chris.
  17. CDRIVE

    How to increase 555 Timer Frequency

    Here, here, I second that! These editing discussions are becoming far too frequent. :eek: Chris
  18. CDRIVE

    switch between wall and battery power

    If it's unregulated then battery current would have to find a path through the rectifier bridge. Normally this shouldn't happen. When a pack is regulated it usually states it. Current can back feed into the output side of a regulator and should be avoided. I'm not sure if I've seen a regulated...
  19. CDRIVE

    How to increase 555 Timer Frequency

    Bob, that would have worked for me before but as you can see below Stu has edited that post. All subsequent posts are now confusing and meaningless. Now I have to kill him. :p Chris
  20. CDRIVE

    switch between wall and battery power

    Are two Diodes really necessary? Unless it's a regulated 9V wallwart, I doubt that it is, the battery can't back feed into it when the mains are lost. In fact it will just add some filter caps across the rails. I think it's only important to prevent the wallwart from feeding the battery. So one...
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