kinda lost could someone look and critque be blunt call me stupid

Discussion in 'The Projects Forum' started by kd7ura, May 6, 2010.

  1. kd7ura

    Thread Starter New Member

    Apr 12, 2010
    27
    1
    ok been puting a circuit together for a voltage monitor and relay on off switch.
    using a LM3914 for the monitor and the first and last led's to trigger the relay on and off is what ive done going to work?
    im about has good with electronics as a newbee.
    ive put together a few circuits with eagle and i have ltspice installed im working on trying to figure it all out.
    the monitor should turn the relay on at 12VDC and off at 13.8VDC.:confused:
    the atached files are for eagle 5.0
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Scale LM3914 input so that 14.7V just lights # 10 LED. # 9 will light @ 13.8V & # 7 will light @ 12V. Use PNP transistors with 2.2k's base to cathode of LED's[white]. If you need help with logic, someone will be back.
     
  3. kd7ura

    Thread Starter New Member

    Apr 12, 2010
    27
    1
    ill be making a diagram of the trigger circuit on the relay board that this circuit will tie into ive downloaded the pdf's on electronics from this site im going to be reading all of it asap been so long for me since ive tried any circuit building.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    It'll help a lot if you post your schematic as .png image files instead of Eagle .sch/brd files. I have Eagle, but it's 4.16r2 and can't read files created by newer versions. My Eagle is registered, and I don't feel like paying several hundred dollars to upgrade it.
     
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Did you find a magnetic latching relay? One or two coils?
     
  6. kd7ura

    Thread Starter New Member

    Apr 12, 2010
    27
    1
    the relay i have has a trigger voltage of 12VDc at 1.2ma
    non latching. are ther any electronic design programs that are simple
    for making a basic schematic are free and can produce a gif or jpg image
    ive got eagle 5.? free , pads, win cad, and a few others downloaded
    none are simple,complex libraries got to pick a package for every thing . how bout just basic symbols layout and print.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    I press the PRINT SCRN key when the schematic is on my monitor's screen then paste it into Microsoft Paint program. Then I save it as a PNG file type.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    Before you post your schematic, please have it conform to some basic rules:

    1) Inputs come from the left, outputs go to the right.

    2) More positive voltages near the top, more negative towards the bottom.

    3) Use Vcc/Vdd/GND/Vee/Vss symbols rather than having wires for such things running all over the place; as they detract from the purpose of the schematic.

    If your schematic is neat and well-presented, you will receive much more useful commentary than if it is not.
     
  9. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,172
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    Some thoughts: In normal operation battery,B. V is from 12V to 13.8V. If BV falls below 12V, LED 7 goes out turning off first PNP, 2nd on momentarily closing Ry 1, Ry 1 latches via Ry2 NC contacts & Ry1 NO contacts. When BV rises to 13.8V LED 9 lights turns on, turning on 3rd PNP momentairly closing Ry2, causing Ry1 to drop out. C1, C2 around 10μF to 50μF. A 68uF closed a 270Ω, 12V relay. R5, R6 provide a discharge path for caps, 100k to 1M
     
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