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  1. K

    Identify a diode? Capital H

    If it's an old diode, it was manufactuered by Hughes Electronics...as in Howard Hughes. Ken
  2. K

    Can't find the right tech part

    What frequency and amplitude of vibrations do you want to count?...1 bump per hour?...3600rpm?...??? You need a lot more details. How about describing the whole project. Ken
  3. K

    Heating System

    It's mostly a lack of information. I see you having to answer or elaborate on the same issues over and over again. You mentioned in one post that you wanted the project to be under $50, but without this info people are proposing solutions that cost hundreds. You said that this was not...
  4. K

    Heating System

    abuhafss, Do you realize that you're spreading your many questions on "one" project over half a dozen different forums (at least the ones I'm aware of) and I don't know how many different threads, as if everyone knew what you are trying to accomplish. If you want to use several forums, you...
  5. K

    alarm panel

    For 24V I would double R1-R4 to 2.2KΩ. C1-C4 can stay the same. Again, R6 may or may not be needed, but if the SCR isn't latching, also change it to 2.2KΩ. Ken
  6. K

    alarm panel

    With what info I have, this did work. The SCR1 is a sensitive-gate type. Any equivalent should work. R5 may or may not be needed, or the value might be different. It's there to assure that the SCR1 has the minimum current to latch on, if the buzzer doesn't provide it. One possible issue is...
  7. K

    alarm panel

    Do you know what the current draw is for your modular 12V and 24V LEDs? Do you know what the current draw of your buzzer is? Is the buzzer an electromechanical buzzer or an electronic annunciator, like a Sonalert. Ken
  8. K

    alarm panel

    Would you be willing to have separate LED's and limiting resistors? If not I might be able to work around that. Do you know the spec's on the indicator LEDs...voltage?...current? resistor value? Ken
  9. K

    alarm panel

    Andy, I just looked at your other thread. It's better if you keep all your questions about a single project in one thread, even if they involve a separate, but related function. That way things like my last question would have been unnecessary. ;) I think I have a workable solution, but I...
  10. K

    alarm panel

    Thanks. That helps. Are there current limiting resistors in series with each of your LEDs, or are they modular LED indicators that have built-in resistors? Ken
  11. K

    alarm panel

    Please post a schematic. :) I may have a solution. Ken
  12. K

    Heat/Cooling System

    That circuit has no temperature control. The two major problems I see in your project are: 1. Rapid, precise, controlled heating of your mold to a high temperature. 2. Doing the project for under $50 In an industrial situation I would use a mold with several high power cartridge headers...
  13. K

    Heat/Cooling System

    ??? You referred twice to a soldering "gun" in this thread. http://en.wikipedia.org/wiki/Soldering_gun It looks like you have your mold mounted on a post that's inserted in the end of a soldering iron. If temperature is not too critical you could use a light dimmer to control the voltage to...
  14. K

    Heat/Cooling System

    How do you intend to use "the components of a soldering gun"? They are just a specialized transformer (line voltage primary and a one-turn secondary) and a switch. And sometimes, 1 or 2 penlight lamps across the secondary. Got a picture of the mold? Ken
  15. K

    Heat/Cooling System

    No experience with them, but sounds like a much better choice. Ken
  16. K

    555 based flasher with dual timimgs

    http://home.cogeco.ca/~rpaisley4/LM555.html#3 Run the 555 at 5VDC. Parallel R1, with a second resistor and PNP transistor (2N3906) in series. PNP's emitter to (+), PNP's collector to one lead of the second resistor, the other lead of the second resistor to Pin 7 of the 555. Another resistor...
  17. K

    Solenoids

    Some solenoids are rated for intermittent duty, some for continuous duty. What is the manufacturer and model # of you solenoid? Ken
  18. K

    Heat/Cooling System

    You can probably do your timing with two LM555 (or an LM556) timers ICs, in monostable configurations. You won't need relayB /switch. I think you will be disappointed with the windshield washer pump. I've tried using several different ones in the past. All of them had nylon bearings in the...
  19. K

    Schematic editor

    With ExpressPCB, I export the schematic at 300ppi BMP. I than edit it with Microsoft Office Picture Manager, cropping to size and exporting to a GIF format. This gives a very readable, small size file for posting. Ken
  20. K

    low frequency timer

    You will not achieve that with any simple circuits, even crystal. You would have to source a radio link to an atomic clock. Or in the United States, source to the 60Hz power line. Extremely good long term accuracy...except for power outages. :( ken
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