Search results

Search Forums New Posts
  1. hevans1944

    HELP ME PLEASE......

    I just re-read your original post and the answers that followed. Perhaps we have a language problem here. I have no idea what your electronics background is, why you decided to study for and receive a diploma in ECE (whatever that means), or where you want to go in an electronics career. But...
  2. hevans1944

    PNP transistor in CLass B push pull amplifier

    Moral of this story: you need to have all of the schematic and all of the parts to understand what is going on. The original image was probably part of a tutorial (maybe this one), and the associated text probably provided an explanation as @Colin Mitchell and @BobK did here. Can't argue with...
  3. hevans1944

    Part CQ1308 U2060G From a Grid Tie Inverter

    Could it be this Chinese import? Congratulations on getting that puppy working again!
  4. hevans1944

    HELP ME PLEASE......

    Clearly, the course that led to the award of "DIPLOMMA IN ECE" was somewhat deficient in preparing students for the real world of electronics. None of us here is able to correct that. Sorry for your bad luck, but as @Ratch said, if you ask specific questions we will try to help you understand...
  5. hevans1944

    PNP transistor in CLass B push pull amplifier

    Perhaps it would help if you provided a reference to where this circuit came from. I don't see how it could possibly work either.
  6. hevans1944

    LED sign help

    You are totally wrong in your understanding of this circuit, which can be found here: First, the authors of this circuit say that there will always be TWO LEDs on at any particular time. One will fade off as another fades on, then second one of those two will fade off and the first one will...
  7. hevans1944

    PWM to 0-10v

    @PRIYADHARSHINI I just now noticed that the you have reversed the inverting and non-inverting inputs to op-amp U1B, creating positive feedback from the output to the non-inverting input. The junction of your feedback resistor, R3, and the input resistor, R4, must connect to the U1B inverting...
  8. hevans1944

    Capacitors

    @Gryd3 when the sensor project was still in the concept stage a few years ago, one of the bio-engineering people consulted with me for ideas. Using active radar to remotely request data transmission seemed to be a viable approach. This would only require a small "patch antenna" to pick up the...
  9. hevans1944

    PWM to 0-10v

    Can we re-visit this problem? What do you mean when you say 2-4 V pwm? A pwm signal is constant amplitude pulses with a variable pulse width. If you apply this to a low-pass filter the result can be a 2-4 V DC output, depending on duty-cycle and perhaps with some ripple that depends on the pwm...
  10. hevans1944

    D flip flop

    The equation you wrote is incorrect. That should be exclusive or not inclusive or.
  11. hevans1944

    Anyone know about LED video wall?

    Viss Lighting offers a quality product used around the world. I can appreciate your desire to "Buy American" but China produces the least expensive LEDs available anywhere. If you insist on only using a product "made in America" be aware that the LED components probably originated in Asia...
  12. hevans1944

    Capacitors

    Yeah, I looked at some with Li-ion cells. Expensive. And the stores I visited (Wal-Mart, Home Depot, and Lowe's) don't tout the life advantage of Li-ion over NiCd, perhaps because they now have tons of stock with NiCd cells installed they want to get rid of. I agree completely with your...
  13. hevans1944

    LPF and HPF

    You and I can do almost nothing to stop it. All we can do is fear it, embrace it, and learn how to live with it. Yes, it truly is a transparent world... and I am not sure that is a "good" thing or a "bad" thing. I grew up in an area of the country where folks were very private, often refusing to...
  14. hevans1944

    Capacitors

    Oops. I missed that. Good point. I would either reduce the size of the battery backup or increase the energy into the capacitor, aiming for perhaps three or four days to recharge instead of eight years, depending on the average energy available from the environment. My only point is this: as...
  15. hevans1944

    8-Pin Development Board

    Thank you. I've started a conversation with you and the two principals involved in the project.
  16. hevans1944

    LPF and HPF

    I love the Internet and the World Wide Web. It is the greatest innovation in communication since the invention of writing. As for privacy, good luck finding any of that with modern technology doing the snooping. Many years ago I worked for a company heavily involved with work for the...
  17. hevans1944

    Capacitors

    Gee, Bob... where are you getting your numbers? The battery and the capacitor are two separate entities, and neither has been fully specified in this thread. In my energy harvesting example, practical versions do exist! As long as energy is being placed in the capacitor at a greater rate than it...
  18. hevans1944

    Circuit Help

    You are trying to interface to an obsolete ARM Cortex M3 processor. Download the data sheets for both the processor and the DAC, read and understand them, then connect the two components with insulated wires. Why are you using an obsolete, soon-to-be-discontinued processor? Texas Instruments...
  19. hevans1944

    Hi There!

    Glad you found yet another use for isopropyl alcohol, my "go to" solvent for most things electronic.
  20. hevans1944

    Electronic Swing Device

    Is it to swing on a vertical axis, a horizontal axis, or something in between? How far (angle of rotation) do you want it to swing? What is the period of the swing? Can you provide a photo and the dimensions of the sign?
Top