Relay SSR with 5v ext



  • Recently I saw some posts on the forum while consulting how to use ps_on and found something that got me thinking, the first thing is about the image, what would happen if in the case described in the image also connect the USB port say to the computer resulting in the Duet board will have the three types of power +5V simultaneously?

    0_1561169585874_2019-06-21.png

    and I also found that if external +5V is powered by the diode, the real voltage is not going to be 5v, and that there would be problems such as for example with the Bl_touch and LCD screen, then what to do in those cases, because if I feed by USB and I have 7i LCD, the USB current is insufficient and the screen is black.


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    @jhonf441 said in Relay SSR with 5v ext:

    Recently I saw some posts on the forum while consulting how to use ps_on and found something that got me thinking, the first thing is about the image, what would happen if in the case described in the image also connect the USB port say to the computer resulting in the Duet board will have the three types of power +5V simultaneously?

    That's OK. Most likely the internal 5V regulator will supply all the power, because of the diodes in series with the other sources.

    and I also found that if external +5V is powered by the diode, the real voltage is not going to be 5v, and that there would be problems such as for example with the Bl_touch and LCD screen, then what to do in those cases, because if I feed by USB and I have 7i LCD, the USB current is insufficient and the screen is black.

    The 7i works with the reduced voltage on the 5V rail. I suspect the problem is that the USB port you are using is unable to supply the total current required by the Duet and the PanelDue, so the voltage on the 5V rail is even lower..



  • Thank you very much.


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