Need help reading schematic

Discussion in 'General Electronics Chat' started by naitek, Jun 4, 2008.

  1. naitek

    Thread Starter Member

    May 31, 2008
    15
    0
    Hello everyone;

    i am new to this stuff, but i would like to get some help understanding where the +V is coming from from a particular schematic.
    in this schematic, i don't understand where the chassis ground is supposed to be neither the voltage coming in.

    I also would like to know where in this schematic, is the voltage outgoing as well.
    link here: http://zerofossilfuel.googlepages.com/324pwm_sche_with_current_limit.gif
    any help would be greatly appreciated.

    -naitek
     
  2. Caveman

    Active Member

    Apr 15, 2008
    471
    0
    The +V is an input voltage from some sort of power source. The +12V is also required. Ground comes in at the ground symbols which are all connected together. The intent of the circuit seems to be to drive pulses of current through the device labelled "cell".
     
  3. BkkChris

    New Member

    Jun 3, 2008
    5
    0
    If cell is supposed to be a solar cell here then that would be your power source and V+ would be your output. The 7808 would be providing regulated power for the oscillator/comparator circuit which appears to be intended to switch the solar cell on/off in a fashion similar to a switching supply and hence reduce the voltage output of the solar cell. This could be used to reduce the output voltage but still maintain efficiency (not waste energy). I am suggesting this as it has a label about ZeroFossilFuel. If in fact that cell device is something else then I think the description above is right. It would seem that 12V input is a reference voltage, and hence probably needs to be provided from an external source, though I wonder at that since it's not too convenient depending on intent of use. The only thing I find odd is that generally switching circuits would have an inductor to store energy in and this one doesn't but perhaps that's not needed if intent is only to lower the output voltage. One might use such a circuit to provide 12V output from a solar cell that may actually generate 17V-20V (typically) and in a situation where your'e not charging a battery so don't want the high output voltage.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Nope, the cell is an electrolysis cell. This is another create hydrogen gas and boost gas mileage scheme. The ZeroFossilFuel is the clue.
     
  5. naitek

    Thread Starter Member

    May 31, 2008
    15
    0
    Hey everyone.

    i will attempt to add my 12V source to all inputs. All grounds should be going to pin 11 --> chassis ground then?

    thanks
     
  6. naitek

    Thread Starter Member

    May 31, 2008
    15
    0
    Hey all again. I still don't get it!
    Am i supposed to take my 12V power supply & connect it to all labels +V, +12, etc and connect all grounds to -V supply voltage. If so, then what am i getting as output voltage to the cell.

    BTW. it is a HHO pulse width modulator taken from myers' design and adapted by ZeroFossilFuel.

    it works dreams for my car so far, but i am trying to learn more on the electronics stuff.

    thanks again to everyone for helping me out.

    -naitek
     
  7. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Now I don't get it... it works dreams for your car, but you don't know how to hook it up? How was it hooked up when it was working dreams?:confused:

    You mean this? http://zerofossilfuel.googlepages.com/index.html I found it quite... um... entertaining. I especially like the part about "shorting one end together" on the three-ended 16 gage wire.:D
     
  8. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    3,373
    1,159
    You can mark me down as a non-donor.

    I wonder how many people do donate to the cause ...
     
  9. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    It would be more correct to say Pin 11 is connected to chassis ground. Chassis ground is a reference. It is also the negitive lead on the battery.

    In the second post Caveman's responses should have answered everything else.
     
    Last edited: Jun 5, 2008
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