photogate scr trigger

Discussion in 'General Electronics Chat' started by Joeshmoe, Apr 29, 2007.

Thread Status:
Not open for further replies.
  1. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
  2. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    can you post a schem of what you are trying to do? this way we can clearly direct you to solving your problem.

    moz
     
  3. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    i hooked up the trigger output to the scr im not sure what kind of schem you want i would like to give you any information you need to help me thanx
     
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Here's the schematic. I can't for the life of me figure out how this is supposed to work. The load has one side connected to ground and the other side connects through the SCR to ground.:confused:
     
  5. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    im not sure what your saying but if you tell me what you need i can get it for you
     
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Where is the schematic? :confused:
     
  7. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    all the info i have is in the first post theres no schematic but there is something on how the trigger is made
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
  9. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    This will trigger when the light from the LED is blocked. If you need it to trigger when the the light is not blocked, swap the position of the phototransistor with the 100k/1k series resistor combination.
     
  10. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    thanx for the schem but it doesn't seem to work... it it is possible that i am not wiring it properly i havent been working with schems like this for that long i am getting inconsistent readings and its just not triggering it
     
  11. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    http://www.hiviz.com/kits/instructions/images/bb_125.jpg The two-conductor cable is the load. Red connects to the SCR o/p and black connects to ground.

    My question: Once the SCR is triggered, electrons are supposed to flow from ground, through the SCR and the load, and then back to ground?:confused: Does the load contain an independant power source?
     
  12. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    I did hook it up that way and it didnt work.. i think the problem is that the voltage difference is not large enough (between blocked and not blocked).trigger does have a 9v battery.
     
  13. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    The trigger circuit has a 9v source, but what about the load? What about the thing that gets triggered? Looks to me like it has both sides connected to ground.:(
     
  14. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
  15. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    i think the problem is that the voltage isnt raising high enough...when the beam is uninterrupted it is at about .3 volts and when interrupted it is about .45 volts
     
  16. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    If you're talking about the gate voltage, you may have too much ambient light on the phototransistor, or you need to adjust the pot, or both.
     
  17. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
    66
    0
    Last edited by a moderator: Nov 11, 2011
Loading...
Thread Status:
Not open for further replies.