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  1. hevans1944

    Damaged Crystal

    I always clean a board after soldering by using a so-called "acid brush" dipped in 99% (anhydrous) isopropyl alcohol. Soak and scrub vigorously and rinse with same. Then blow dry and inspect. Repeat until there is NO visible residue. But I guess you know that procedure by now!
  2. hevans1944

    Transmit Information over Radio Signal

    It would help if you described in some detail exactly what you hope to accomplish. What radio frequencies do you intend to use, what is the power input to the transmitter, how fast and how accurately do you want to send (and receive?) addresses or names or "numbers stored in a chip" and where is...
  3. hevans1944

    Advice on finding a part?

    From the Owner's Manual, available on line: Your Inverter requires no maintenance and contains no user-serviceable or replaceable parts. That may explain why they won't help you. Best bet is to take it to an authorized service dealer or get a Return Authorization Number from Tripplite and ship...
  4. hevans1944

    230v relay switching problem with rf

    You talk about "RF Receiver side" without specifying what signal you are intercepting from the "RF Receiver". Is there an "RF Transmitter side" too? Are you trying to actuate the relay when the transmitter signal is received by the "RF Receiver side?" What are the timing requirements for the...
  5. hevans1944

    DAC0800 calculation I out

    Okay. Download and read the datasheet here. All your questions will be answered by reading the datasheet, which has many example applications.
  6. hevans1944

    Please Help! I need some expert advice to specify a component

    Welcome to Electronics Point, Sean! Can you provide a little more information about what kind of electric hydraulic ram you are using? These come in a huge variety of sizes and capabilities and configurations. And what do you mean "is being forced against its will in the rest state"? Last time I...
  7. hevans1944

    Momentary Switch circuit help!

    That is a real inconvenience, racking the slide for each "shot," but then this is just a "simulation" of real firing. The best way to work on focusing and sight picture, IMHO, is at the range with real ammo, preferably the type you will carry in your pistol. This may help explain why I have not...
  8. hevans1944

    Timer to trigger another timed pulse

    Look also at the two breadboard pictures posted in the reviews on the Amazon site. They show two timers connected in a loop so the first triggers the second which triggers the first again.
  9. hevans1944

    Help With Lock Circuit - Transistors

    Exactly right! The display remained lit, but it was somewhat difficult to stare at it and manipulate the keypad buttons simultaneously. Most users would "find" the positions of their numbers on the display and then look away to the keypad to punch in those numbers, perhaps looking back to the...
  10. hevans1944

    Help With Lock Circuit - Transistors

    I don't even want to open this can of worms now that @KrisBlueNZ has chimed in. But I will think about it overnight. On push-button combination locks: The best one I have ever seen was in the entrance to a highly secure area. It consisted of a plainly visible numeric keypad with blank keys and...
  11. hevans1944

    Momentary Switch circuit help!

    I was thinking about building one of those things that would slip into the barrel from the breech. On the commercial version, "O"-rings hold it in place and center it in the barrel. There is no extractor lip at the breech end, so the device is "extracted" by pushing it out with a rod inserted in...
  12. hevans1944

    Timer to trigger another timed pulse

    There are three terminals (CK, COM, CB) connected to a single-pole, double-throw, relay. These three terminal are located at the same end of the board where the relay is located. These three terminals connect only to the relay, not to other circuits on the board. There is a normally-closed...
  13. hevans1944

    Frequency Generator?

    I wasn't even gonna mention that GPS-disciplined rubidium clocks are the cats meow. Plus they run pretty good even if the GPS constellation goes south (for whatever reason). I do believe the cesium atomic clock is more stable, but being based on a microwave-frequency hyper-fine transition...
  14. hevans1944

    LM358 Breathe light

    Yeah, that sort of works. Many non-polarized motor-starting capacitors are made that way, I think. I prefer NOT using electrolytic capacitors as RC timing components. Their capacitance is all over the map, specs like -10% to +75% being not uncommon. Probably work okay for this project though.
  15. hevans1944

    Frequency Generator?

    You didn't say which Ramsey 30 M kit you have... may I assume it is a QRP receiver like the own offered here? If I needed a 2 kHz signal I would generate a 2 kHz signal. If the 2 kHz signal needed to be the exact second harmonic of a 1 kHz reference signal, I would divide the 2 KHz signal by...
  16. hevans1944

    Trying To Cheat The Laws Of Physics . . . Again. Multi Voltage Power Supply

    FB! There is an on-line course I signed up for in preparation for my Technician, General, and Extra Class exams. I highly recommend HamTestOnlne. There is also plenty of free study stuff online too, but you probably have looked into that. I would also recommend that you study for all three exams...
  17. hevans1944

    Trying To Cheat The Laws Of Physics . . . Again. Multi Voltage Power Supply

    I dunno about early definitions of QRP, but today the ARRL defines it as 10 W or less input to the final or less than 5 W measured output (to the antenna I presume). My KX3 puts out a maximum of 12 W on a warm day with freshly charged Li-ion cells, and fer shure that much with an external power...
  18. hevans1944

    Converting a projector from incandescent to solid state?

    No projector LED hacking for me. I prefer digital images I can access from my Galaxy 5 smartphone, my laptop, or my desktop computers. Whenever I buy a scanner I always make sure it can scan transparencies, particularly 35mm color positives and negatives. I do like bright white LED replacements...
  19. hevans1944

    Trying To Cheat The Laws Of Physics . . . Again. Multi Voltage Power Supply

    You wouldn't happen to have a radio amateur license would you, what with messin' around on the 30 M amateur radio band? If so, please tell us what class license and your call sign. BTW: I love HF QRP operation and your Facebook page. 73 de AC8NS Hop
  20. hevans1944

    Converting a projector from incandescent to solid state?

    At work, back around 1997 or so when I first started there, I found a really ancient projector that was used to illuminate microscopic dust motes in the air over a "clean bench" used for semiconductor wafer processing. The bright collimated light from the projection lens made the motes sparkle...
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