Opto Isolator

Discussion in 'General Electronics Chat' started by libbylou28, Sep 12, 2016.

  1. libbylou28

    Thread Starter New Member

    Sep 12, 2016
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    I am a student teacher and I am trying to get to grips with this circuit. I have come in half way through a course and a student has designed this and I want to check it will work. The emitter circuit is fine I just need to check that the receiver circuit is correct!!

    My knowledge is ok but need some help with this. upload_2016-9-12_21-41-39.png
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Hi and welcome to the forum.
    I see three problems in the circuit, first of all I cannot see any optocoupler in that circuit, so I don´t really know what you´re asking. Second thing is that the C08 is only good up to 5.5V, while the battery is 9V. Third thing is that D3 is missing a series resistor and will burn out very fast.
     
  3. libbylou28

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    Sep 12, 2016
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    Thank you for the response. The opto coupler will be put into the 3 pin terminal block at the bottom of the circuit on the right. I see what you are saying about D3 and will change the battery voltage. But it's not far off being right??
     
  4. kubeek

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    Sep 20, 2005
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    I still don´t understand, an optocoupler typically has an LED on one side and a phototransistor on the other side, so I would expect two sets of two pins that should convey the signal. Frankly I have no idea what the bottom half of that circuit is supposed to do. Could you ask your student to actually specify the optocoupler and draw it in the diagram, and also say what is the purpose of it? So far I don´t see anything that would need an optocoupler nor what it should be doing.
     
  5. libbylou28

    Thread Starter New Member

    Sep 12, 2016
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    Will do I'll get back to you in the morning and thanks again for your input.
     
  6. Alec_t

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    Sep 17, 2013
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    Why is pin G3 connected to V+?
     
  7. libbylou28

    Thread Starter New Member

    Sep 12, 2016
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    No idea!! The bottom of the circuit confuses me I know the circuit is based on a project board you can buy. I know the infra red receiver part number is 55-0620 and is a vishay TSOP4838 Infrared Receiver 38kHz any ideas would be welcome!!
     
  8. Alec_t

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    Sep 17, 2013
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    What connects to CN2?
    Presumably CN1 connects to CN3?
    Shouldn't there be a ground (B1-) connection to CN1?
     
  9. libbylou28

    Thread Starter New Member

    Sep 12, 2016
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    CB 2 was a piezo sounder.

    CN1 and 3 connect
     
  10. Alec_t

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    No ground connection for whatever CN1/3 send to or receive from?
     
  11. libbylou28

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    Sep 12, 2016
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    I'm not sure this is where my knowledge fails me!
     
  12. Alec_t

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    If a TSOP4838 connects to C4 it will require a ground (i.e. B1-) connection. No such connection is available via CN1/3 with CN1 wired as shown.
     
  13. libbylou28

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    Sep 12, 2016
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    Ok that makes sense although not sure which pin on CN1 to connect to ground. Thank you by the way you have been very helpful!
     
  14. kubeek

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    Sep 20, 2005
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    Then ask your student where he wants to connect it.
     
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