How do I create a current threshold?

Discussion in 'General Electronics Chat' started by ericwoz, May 30, 2016.

  1. ericwoz

    Thread Starter New Member

    May 30, 2016
    I have solar project with a 9v 500 mA solar panel tied to a voltage regulator, powering a 3v Radio (there is no electricity available in this location). It works most of the time when the sun comes up, but sometimes it won't start in the morning when the sun comes up. When it doesn't work, I have to cover the panel and then uncover it to get it to work. I was wondering if the problem might be the slow increase in current when the sun comes up. Should I have some sort of switch to prevent power going to the radio until the minimum current is being supplied by the Solar panel? If so, what electronic component would do that? Any suggestions would be greatly appreciated.
  2. AlbertHall

    Distinguished Member

    Jun 4, 2014
    You might get this to work by using a regulator with an enable input. A simple single transistor circuit could then drive the enable when the input voltage to the regulator was high enough (what level would need some experimentation).
  3. BR-549

    Well-Known Member

    Sep 22, 2013
    What does your voltage regulator data sheet say about it?

    They make voltage regular circuits and ICs especially for solar panels.
  4. ericwoz

    Thread Starter New Member

    May 30, 2016
    Thank you this is very helpful!
  5. ericwoz

    Thread Starter New Member

    May 30, 2016
    Thanks, I didn't realize that. I will look and see if I can find one that works for my solar panel and radio. I'm using the one listed below, but it's not designed for a solar panel for supply power.
    SchmartBoard - Power Management Modules
  6. crutschow


    Mar 14, 2008
    Does the radio work if you just shut it off and then back on?