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  1. hevans1944

    8-Pin Development Board

    So I can use the board I receive in the mail (eventually) without track modifications? Yee Haw! I've got a fine-point Sharpie around here somewhere... Are we ready for some A/D programming? Need any help with that?:p
  2. hevans1944

    Need help to understand the amplifiers circuit

    No "maybe" about it. The description in the paper is wrong, unless you add another resistor of value R between the non-inverting input and circuit common. That could just be an oversight in drafting the schematic, but someone should have proof-read it and corrected it before publication. If I...
  3. hevans1944

    8-Pin Development Board

    Yeah, somewhere in another thread I noted that Microchip engineers would multiplex power and ground on one pin if they could figure out a way to do it. No it does not. Electricity knows diddly about resistance. We may observe that in a parallel circuit more current flows in the lesser...
  4. hevans1944

    Need help to understand the amplifiers circuit

    I get the same result. Looks like the non-inverting input needs a resistor of value R connected to common.
  5. hevans1944

    scph70100 ac adaptor

    If you do decide to attempt to repair it, you will probably find the case seams are welded together for your protection. It takes skill and precision to cut through those seams with a small saw and not wreck the circuitry inside. It is easy to cut too far and rip into a transformer winding...
  6. hevans1944

    Low value resistors

    I used to know someone who earned a living building custom motor testing equipment. He used some really big reed relays to switch the various motor currents. He custom-built reed relays by purchasing the reed switches, which were custom-made with certain alloy contacts to his specifications...
  7. hevans1944

    Need help to understand the amplifiers circuit

    Show us your calculation.
  8. hevans1944

    Need help to understand the amplifiers circuit

    The first stage is "looking" at three-phase power, two phases at a time, A-B, A-C, and B-C. The second stage compares each of these to ground, outputting square waves. Is this a homework problem?
  9. hevans1944

    Small $5 Project Board

    Why don't you make friends with Google and look here.
  10. hevans1944

    8-Pin Development Board

    Don't pitch it yet! Try removing the caps you have in parallel with the pull-up resistors for the two tactile switches. The PICKit 3 cannot drive pins 4 (Vpp), 6 (ICSPCLK) and pin 7 (ICSPDAT) if any of these pins has been "by-passed" or loaded (like with a potentiometer!). I have always used the...
  11. hevans1944

    Best Basic Telephone Recording Interface Circuit To Build ?

    In the previous century, in the United States of America, telephone service was a monopoly controlled by Bell Telephone, somewhat affectionately also called Ma Bell. The technology used for telephones originated from a wholly-owned Bell subsidiary, Western Electric. Both companies tightly...
  12. hevans1944

    Wanted: Looking to mini video camera.

    Wow! You are gonna get SPAMed big time posting your e-mail addy in an open forum. Do you have any idea how many 'bots roam Electronics Point at any given moment?
  13. hevans1944

    Need help with android app for Bluetooth device

    Hey! This is a serious Forum. I bet he plans to mount it on the propeller shaft of the speed boat you can almost see in his avatar.:cool:
  14. hevans1944

    8-Pin Development Board

    You can wait a few days until the component-side fully "cures", then hold the board vertically with the bottom edge over some paper towels or rags while you apply the alcohol. Let the excess flow down the board to be absorbed by the towels. Might want to fill a small plastic spray bottle with...
  15. hevans1944

    Best Basic Telephone Recording Interface Circuit To Build ?

    I thought 'phone phreaking ended when cell phones became widely available.
  16. hevans1944

    8-Pin Development Board

    Nice job soldering the through-hole components, John. Now go scrub the flux off with 90% isopropyl alcohol using an "acid brush" with the bristles cut short to stiffen them up. Or use a stiff tooth brush.:)
  17. hevans1944

    Digital calendar which flashes a LED when out of date range

    The Pluto project is indeed a tour de force in reverse engineering and re-purposing... they did keep the case and the LCD, but all the electronics were replaced. I like my original suggestion of using a clock oscillator to interrupt a PIC every minute to update a software clock-calendar...
  18. hevans1944

    8-Pin Development Board

    Looks pretty good even with a few specks of dust. Maybe I can buff those off with a green pad and spray some clear Krylon enamel over it. Back in the day, I used a technical pen with India ink to apply outlines and dry transfer letters to apply text. Sprayed on two or three coats of clear Krylon...
  19. hevans1944

    Digital calendar which flashes a LED when out of date range

    There are literally hundreds, if not thousands, of inexpensive digital watches with a bult-in alarm function. Just pick one with the features you want and hack it. That means bringing the button switches out to easily accessible front-panel switches, figuring out some way to translate the pulsed...
  20. hevans1944

    8-Pin Development Board

    Probably not. I have a good assortment of resistors and capacitors, and I think a few tactile push-button switches and some 8-pin IC DIP sockets. No surface-mount devices yet. I am going to see what kind of capacitor and resistor assortments are inexpensively available from China. No hurry on...
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