No output from 7905 when in increased current

  1. Hi. no output from 7905 when configured in high current mode and parallel transistor short circuit protection. please see the attachment for circuit diagram. the load connected to the output is 100 ohm (50mA).
     

    Attached Files:

  2. jcsd
  3. berkeman

    Staff: Mentor

    The LM7905 is a negative voltage regulator. So Q1 is backwards, and your polar capacitors are upside-down. You should also show the ground connection on the 7905.
     
  4. berkeman

    Staff: Mentor

    Actually, a bunch of stuff looks wrong in that circuit. Where did you get it?
     
  5. some corrections made. the problem is as mentioned before.
     

    Attached Files:

  6. berkeman

    Staff: Mentor

    If you hook it up as just a plain 3-terminal regulator without the extra dropping transistor, does it work?
     
  7. the project is in freeze stage as soon as i finish it i will let forum know about the results.
     
  8. 7905 was damaged! i replaced it and initial test shows the circuit is working.
     
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