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  1. hevans1944

    Which Touch Display?

    Why not go to this site, buy one, then take it apart to reverse engineer it? Even if you can't put it back together, you will at least have the components you need. There might even be a makers mark on some of them.
  2. hevans1944

    What components do I need??

    Sure you could. Just hire a dozen kids who happen to be very good at what you need to do to bring the product to prototype stage. Pay them with stock (no par value) in the company you form. Then sit back and wait for an angel investor to step in with funding for production, also in exchange for...
  3. hevans1944

    transformers back to back - why won't work?

    This is actually a poor man's way to make an isolation transformer. Real isolation transformers, those with reasonable power handling capacity and Faraday shielding between primary and secondary, cost big bucks. If all you want to do is isolate your 120 V AC load from mains power, two control...
  4. hevans1944

    What components do I need??

    Possible covers a lot of territory. It is possible to send men to the Moon and safely return them. How much support did that require? It is possible to make a fitness band with all the features you describe. How much support do you think that requires? Good ideas are a dime a dozen. Always have...
  5. hevans1944

    Pie Network , Transmitter Tuning and Loading Questions

    @Y2KEDDIE may not have an amateur radio license yet, or even be interested in obtaining one. However he is a seasoned, experienced, and well-qualified electronics technician. As long as he keeps his "transmitter experiment" confined to exciting a non-radiating dummy load, i.e., the Bird watt...
  6. hevans1944

    Pie Network , Transmitter Tuning and Loading Questions

    You still need C2 because its reactance is part of the tuned circuit, consisting of C1, C2 and L, that matches the output impedance of the tube to the load impedance. But since this is an "experiment" you are free to do as you please. Please let us know how that turns out for you. The value of...
  7. hevans1944

    LPC21xx Microcontrollers

    Oh, yeah, I barely scratched the surface of PWM applications... and of course you don't really need a microcontroller; discrete components can be easily assembled into a working PWM application. Microcontrollers just make the control task relatively easy. One area I have been investigating is...
  8. hevans1944

    LPC21xx Microcontrollers

    The watch dog timer is used to set a hardware interrupt when an expected future event has NOT occurred within the time allocated by the timer. This means if the event DOES occur, the program must reset or disable the watch dog timer to prevent the watch dog interrupt from occurring. This allows...
  9. hevans1944

    Pie Network , Transmitter Tuning and Loading Questions

    I recommend that you borrow or purchase a copy of any edition of the ARRL Amateur Radio Handbook for information on how pi networks (and electronics in general) work. Those capacitors are RF tuning capacitors and are part of a resonant impedance matching network between the tube and the...
  10. hevans1944

    bridge rectifier circuit

    Is the energy harvester a magnet that moves back and forth within a coil of insulated wire? If so, you should be able to float the two terminals, Connect them to the junction of D1 and D4 and to the junction of D2 and D3. Then "ground" if necessary either Node 1 for negative output from Node 2...
  11. hevans1944

    bridge rectifier circuit

    It looks like your 4 Channel Oscilloscope +ve pin and -ve pin are not true differential inputs. Probably the -ve pin is chassis common and also in common with the "ground" side of V1. You will obtain full-wave rectification between Node 1 and Node 2, but not referenced to "ground". You should...
  12. hevans1944

    What steps do i have to take to make an electronic calculator?

    The first step I would take if I were you is a review of available calculators that perform the functions you want your calculator to perform. Then I would compare their selling price against the cost of building your own calculator. You will probably be able to cannibalize an inexpensive...
  13. hevans1944

    3 output SR latch

    If any of the inputs x, y, or z transition to 1 state, you want the associated output a, b, or c to transition to 1 state and remain there after the associated input returns to 0 state. Correct? What happens if more than one input transitions to the 1 state? How do you reset an output to 0...
  14. hevans1944

    Assistance with Transistor Theory

    Years ago, when I first started puttering around with BJTs (we just called them transistors back when) after years messin’ around with vacuum tube circuits, I recall having a hard time understanding how they worked. I knew the base layer must be pretty thin, the emitter heavily doped to provide...
  15. hevans1944

    Level Measurement System

    Okay, I just read your profile page. Congratulations on trying to pick up where you left off in college. No matter how little you learned or remember from that experience, it's still better than starting from ground zero. And welcome to Electronics Point! Members here are more than willing to...
  16. hevans1944

    ID'ing/replacing surface mount device

    The right ends of the pair of components on the left side appear to be soldered to a ground plane of sorts and are also in common with the right ends of the right pair of components. In other words, this ground plane (if that is what it is) has a common connection to all four components. The...
  17. hevans1944

    Level Measurement System

    Um, since this is homework, have you actually read the book associated with this class? Also, Google is your friend. This is more a problem in critical thinking than anything else. Ask yourself these questions: What is the purpose of a transducer? You don't have to know how it works, just know...
  18. hevans1944

    Proximity detector/switch

    Funny you should ask this. I have an application in mind, inspired by all the personally-worn electronics (watches. fitness monitors, etc.) appearing on the market lately. There are several possible solutions that I am considering. One of the simplest is a bracelet that uses near-field...
  19. hevans1944

    Help with RS485

    Yeah, let's get the wheels attached and the motor running before worrying about the bells and whistles. Sorry I digressed. Time to go to bed.
  20. hevans1944

    Help with RS485

    . Thanks, Kris. I didn't know those parts existed. So @FuzzyWombatSoup can implement his "star" with just one long daisy-chain. On a slightly different note... One of the nice things about having a μP at each node is you can easily program the address of each node. There are zillions of ways...
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