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  1. hevans1944

    My electromagnetic pulse generator

    Below is an image, to scale, of the Earth in the background against a typical solar prominence that could be a precursor to a coronal mass ejection or CME. What isn't to scale is the 93,000,000 mile distance between the Earth and the Sun. This distance lowers the probability that any given CME...
  2. hevans1944

    My electromagnetic pulse generator

    Excellent questions! Let's all hope we never find definitive answers to either one. But, if I were a betting man, I would put my chips on the CME being the most destructive because it has the full faith and credit of this solar system's largest operational hydrogen fusion reactor to drive it...
  3. hevans1944

    My electromagnetic pulse generator

    Well, he was able to brick a Casio calculator with it from a distance of about two millimeters. Be afraid, be very afraid! What's that old saying? Keep your friends close, but your enemies closer.:D AFAIK, the only practical large-area EMP generator is a nuclear detonation in the upper...
  4. hevans1944

    ISO a particular switch. Don't know what it's called/to look for

    I hate to revive this thread, but has no one actually read the page that @juntjoo linked to earlier that advertises this contraption for sale at Wally-World? Further down the page (use the scroll key) there is a link to the Aqua Cube Fountian Operating Guide. The "Guide" clearly shows that the...
  5. hevans1944

    Capacitor terminals

    The picture you uploaded shows what appears to be a 6 μF, 370/400 V AC, non-polarized electrolytic capacitor, These are typically used in AC split-phase motor applications. An oily substance present on the outside of the aluminum can is indicative of leakage of electrolyte from the capacitor...
  6. hevans1944

    Electret Microphone Help

    Wow! And what did that circuit actually DO for you? Can you post a schematic diagram of the circuit? Not too surprising, given the troll-like nature of your responses to our questions here. Plus, you have not yet uploaded any schematics or photographs... or anything that would help any of us...
  7. hevans1944

    Diode

    Um, wait while I try to find my long-nosed pliers to try to pull some information from the OP that will guide us toward a solution to their problem...
  8. hevans1944

    Burglar alarm.

    I think you have the correct perspective on this. It is obvious that the OP is a newbie and was having difficulty understanding the simple SCR latching circuit. I doubt we have helped much in that regard, but there is little we can do at this point. The OP simply needs to learn a lot more about...
  9. hevans1944

    Burglar alarm.

    I kinda like the "Protected by Smith & Wesson" sign, even though we don't actually use any of their products. But why announce to the world that you have "protection" of any kind? Let it be a surprise. Big dog = mo betta, mo bigger bites. We have a LOT of "big dogs" in our home, but none yet...
  10. hevans1944

    What is up with this?

    Clearly, Rds(on) is irrelevant when the MOSFET is operating in the linear (or so-called "triode" mode), which it does in the Analog Devices Application Note. I can only conclude that the statement concerning the use of a MOSFET with a smaller Rds(on) is a "Red Herring" someone threw in there as...
  11. hevans1944

    IC's temperature ratings

    If that isn't enough to boggle your mind, check out the links on this Google results page that came up when the key words "radiation hardened electronics" was used as the search string. It's not just about about bullets and mayhem anymore: it's tough to survive, much less reliably operate, in...
  12. hevans1944

    Burglar alarm.

    I suggest you read and work the experiments in the order they are given in the book excerpt that @Kiwi posted. In particular, review Mr. Circuit Lab Kit A7 to see how an SCR works. This appears to be a "monkey see, monkey do" introduction to electronics with very limited "theory of operation"...
  13. hevans1944

    Voltage Regulator Help

    @Bruce Johnston welcome to Electronics Point! To expand just a little on Dave's reply... you first need to convert the variable battery voltage (12.6 to 14.5 V DC) to a higher DC voltage that can then be regulated down to your desired 12 V DC. A switch-mode power supply (SMPS) is typically the...
  14. hevans1944

    IC's temperature ratings

    Operating temperature is just ONE factor in qualifying an integrated circuit to military specifications. Testing and documentation of the results of those tests is another. Quality control is a third factor to consider before a part can be deemed worthy of military application. You definitely...
  15. hevans1944

    Signals in circuit

    YES, IT IS HOMEWORK! By your own admission in the above quotation, it fits our definition of "homework" exactly. The screen shot you posted is taken directly from Analog Devices Application Note AN-968 "Current Sources: Options and Circuits. I suggest that you read and understand the entire...
  16. hevans1944

    Gain of operational amplifier...

    Well, the back-to-back diodes across the "Search coil winding" sort of places a maximum limit of ±0.7 V DC (if silicon diodes). However, since it is a "search coil winding" it is likely that the anticipated signal is much less. With a closed-loop gain of 101 and a negative supply rail of -3 V...
  17. hevans1944

    How do i know how many volts my circuit needs?

    Maybe you should consider obtaining help from a more specialized forum, from people who understand guitars as well as electronics. Have you considered DIYstompboxes.com? Here is a thread on that forum that discusses the venerable Baxandall tone control circuit, both active as well as passive, in...
  18. hevans1944

    Gain of operational amplifier...

    It appears (upon further magnification and eye squinting with tongue precisely positioned just so...) that the op-amp is an Analog Devices AD8628 rail-to-rail device. @Ratch's unusually non-pedantic analysis of the DC gain is a spot-on first-order analysis of a typical non-inverting gain. How...
  19. hevans1944

    Temperature sensor project

    Gee whiz... if its "a close working design" why don't YOU do the pcb schematics? Seems to me that I have seen LED digital temperature displays, with alarms, someplace else... why are you re-inventing that particular wheel? As for "the idea and the requirements" just what would those be? Is this...
  20. hevans1944

    Ideas to start my project.

    I strongly agree with this. It is past time, given the current state-of-the-art in electronics technology, to implement a "living thing left behind" alarm system. Children, infants, pets, disabled adults... anyone incapable of freeing themselves from a potentially fatal situation not of their...
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