Hold high circuit?

Discussion in 'General Electronics Chat' started by futbalfantic, Feb 11, 2012.

  1. futbalfantic

    Thread Starter New Member

    May 4, 2009
    4
    0
    Would the attachment work for a hold high circuit?
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Describe in detail what you want your "hold high" circuit to do. Whatever it is, I can pretty much guarantee you that the circuit you posted won't do it.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    What's a hold-high circuit?

    Depending on the voltage levels of VCC and VSS this transistor will be very unhappy.
     
  4. futbalfantic

    Thread Starter New Member

    May 4, 2009
    4
    0
    Basicly this is what I have. A linear actuator that I need to move up and down. The signal is coming from a comparator and pulling it high. I realize it needs to be adjusted for voltage. I'm just trying to get an idea.
     
  5. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    If you want us to help, try to put yourself in our shoes. Realize we know nothing about the specs of your linear actuator (voltage and current requirements, etc.), nothing about your comparator, or your available supply voltages. Do you want to latch the "hold-high" circuit, or do you simply need a high side switch?
    Give us as much info as you can. Too much is better than not enough.
     
  6. futbalfantic

    Thread Starter New Member

    May 4, 2009
    4
    0
    I'm sorry I realize I am the worst when it comes to explaining things. I do not have any details on the acuators or really anything yet. I'm still super early in the design stage. Here is my plan. I am going to have a "sleve" over a clear pipe. A laser will be pointed at a phototransistor. As the voltage across the transistor goes down, it will hit a set point (via the comparator and pot). The "hold high circuit" will move the linear actuator up and the circuit will be cut off by a limit switch. Then the oppsite via the same laser and different com and pot.

    Edit: I realize that there needs to be reistors in a lot of places but like i said this is just a concept design not a functional design
     
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    Sorry, I still don't get it. Perhaps a drawing of your pipe, sleeve, phototransistor, laser, and actuator would help. You probably have a pretty good idea of what this looks like.
     
  8. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    I "think" I understand what you are saying. The laser is shining through the clear pipe pointed at the phototransistor, and when the (opaque) sleeve gets to the point where the phototransistor is it will interrupt the laser beam. Correct?

    Now, the last sentence is not clear: "Then the oppsite via the same laser and different com and pot." How is the actuator being triggered, i.e. when and how it starts to move ?

    You will need to provide the following information:

    1. a "logic" explaining when and how the circuit starts doing what it's supposed to be doing, are there any more switches etc.
    2. the approximate voltage and current ratings of the actuator you want to use. Since you know what you are going to be pulling/pushing with it you will have an idea of the force needed etc.


    As Ron said, too much information is better than not enough. ;)
     
  9. futbalfantic

    Thread Starter New Member

    May 4, 2009
    4
    0
    No more switches. The tube is clear (or has sight windows). The material that fills the tube is a dark color and as it fills in the tube less light will pass through it. (ie: the need for the transistor and pot). I'm not too worried about the power needs as of yet bc I can step up the transistor in darling pairs the meet the needs (correct?). As for the "logic" the tube begins to fill the voltage across the transistor begins to drop via less laser light hitting it. The "set point" controlled by the pot and comparator, when the transistor voltage hits this the circuit is switched on in the "up" position. The voltage will go back up on the "sensing" circuit. Which would stop the actuator from moving. So the need for the "hold high circuit". This would keep it moving until it hits the limit switch. When the voltage hits the other point the opposite would happen.
    Thanks for all the help
     
Loading...