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  1. hevans1944

    Septic Alarm Shorting out

    Bite the bullet and replace the alarm. Hire an electrician (a lecky in Australia) or a septic tank service to troubleshoot and repair this. You are clearly unqualified to be "messin' around" with things connected to household wiring, as demonstrated by your "shotgun" approach to replacing the...
  2. hevans1944

    Inrush Current for Capacitive Load

    The very first thing wrong with this statement is your "impedance formula" where you state the impedance is Z = 1/j*w*C. Last time I looked, the capacitive reactance "formula" is XC = 1/jωC, where ω is the radian frequency, equal to 2πf, and C is the capacatnce. A somewhat similar "formula"...
  3. hevans1944

    Load cells with 9V excitation voltage

    Wow! This project of yours brings back memories from the 1960s when I was then a young electronics research technician assigned to a dynamic fatigue testing machine project. That project used an hydraulic piston connected to a vertical load train and controlled by a high-performance servo valve...
  4. hevans1944

    transformer use question

    Firstly, there is no such thing as a "dc transformer". Transformers operate on ac. You can create dc by connecting the transformer secondary to a diode rectifier. Secondly, solenoid-controlled valves come in two types: ac solenoid coils. and dc solenoid coils. The main difference between the two...
  5. hevans1944

    Freq Generator

    Sounds like this is an SDR or Software Defined Radio since all the "majic" happens inside a single chip. These are a lot easier to produce since they do not need or use those pesky RF transformers with the tuning slugs. I happen to own such a beast for my amateur radio hobby. It uses a rotary...
  6. hevans1944

    IR Beam Break sensor

    Of course I could, but wtf would you learn from that? As an alleged "college student" you should have already learned how to perform your own research, either online or at a library with real books. I would make friends with whatever search engine you like best (I use Google a lot, but there are...
  7. hevans1944

    IR Beam Break sensor

    Ambient light is always something to consider when designing any photo-electric beam-sensing circuit. The first approach to solving this problem is to collimate (make parallel) the beam from source to sensor and then use an aperture, such as a length of opaque tubing at both the source and...
  8. hevans1944

    what mosfet to use for an induction heater

    Gee, whiz, folks. I completely forgot to check into which forum the OP asked their question! The Electronics Homework Forum, of course. We ARE NOT supposed to give definitive answers to questions asked there. Guidance and pointers to the right direction ONLY! So, forget 2N7000 mosfets, 6L6GCs...
  9. hevans1944

    what mosfet to use for an induction heater

    Thanks! @bertus has provided us with minimal datasheets describing the latest and greatest power metal-oxide-semiconductor-field-effect-transistors (MOSFETs) as well as datasheets describing the latest and greatest insulated-gate-bipolar-transistors (IGBTs). That should give the OP, @ahmed...
  10. hevans1944

    what mosfet to use for an induction heater

    Wonderful! I don't know how you find the time to dig out this information, but it is much appreciated. Can you now attach a Zip-file to your next message that contains all the power IGBTs that might be useful? @ramussons suggested this in post #4 but nobody responded.
  11. hevans1944

    what mosfet to use for an induction heater

    What?! You want the poster to present with objective and verifiable FACTS with a link to VALID information? Or as Homer Simpson once said, "Facts, shmacks. You can prove ANYTHING with FACTS! Facts are meaningless. You could use facts to prove anything that's even remotely true.” Well, I am not...
  12. hevans1944

    what mosfet to use for an induction heater

    Induction heating is not complicated. You create a high-powered sinusoidal wave form at a certain frequency. Couple this wave form to an induction coil, wound in such a shape as to enclose the part to be heated. Depending on the power produced, it may be necessary to use a coil made from hollow...
  13. hevans1944

    alternating LED flasher using 12Vdc supply and 555 timer

    SEE MY RESPONSE TO DANA, BELOW. The two of you please note the date of the last posting to this thread: CDRIVE, Mar 26, 2013, post #6. This thread is DEAD and it is quite likely that CDRIVE is too. The last time I tried to talk to him, his wife said he had suffered a stroke. I got the distinct...
  14. hevans1944

    what mosfet to use for an induction heater

    I favor thermionic power tetrode or power pentode forced-air cooled vacuum tubes for high-frequency induction heaters. I did have some experience working with a low-frrequency, inducution-heated, pressure welder installed in a high-vacuum chamber at the General Electric Evendale Plant sometime...
  15. hevans1944

    Random digital potentiometer driving

    This forum is EXACTLY meant for people like you! And me. And @bertus. And a lot of other members you probably haven't met yet, unless you went back and read their contributions in older threads here. I will be 78 years old if I am still alive on June 25th of next month. I have more than...
  16. hevans1944

    Random digital potentiometer driving

    IMO Posts #43 and #44 are heading in the right direction. A hardware solution is almost always "easier" to build and troubleshoot than a "complicated" computer program. I do favor the "complicated" computer program because "mistakes" are easily corrected with just a few keystrokes, assuming you...
  17. hevans1944

    Multiple LED Driving

    @bertus: That is a very interesting article for anyone needing or wanting to wire up a large number of LEDs, especially if the LEDs are unmounted chips, ready to be soldered to a massive heat sink for use as an automobile headlight. For that application, a hard failure of any one LED should not...
  18. hevans1944

    Random digital potentiometer driving

    Okay, this is starting to make sense. The signal generator currently produces a voltage that replaces the voltage produced by the tuning potentiometer in the radio. So far, so good. You now need to generate a timed sequence of pseudo-random but fixed voltages to replace the signal generator...
  19. hevans1944

    Multiple LED Driving

    Yep. LEDs ain't very demanding in how you use them, or even difficult to manufacturer, so they are dirt cheap. I do strongly agree with @Audioguru that if you want components that are built to some specification, then it is quite difficult to obtain them from Asian sources. We have an excellent...
  20. hevans1944

    Random digital potentiometer driving

    That is a somewhat better description of what you are trying to DO, but it still includes an unexplained requirement on HOW to use a signal generator to control the tuning of a radio. Why is that? I thought you wanted to select a radio receiving frequency at random? How does a signal generator...
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