Hello all I am having a problem using a uno with an rtc and relays connected. When I flash the uno with my sketch and the time is out of spec I expect the lighting relays to remain off they do, until I disconnect the computer from the uno (uno, relays etc being powered from separate 5v psu) then o…

Relay turns on when computer is disconected

Wawa April 2, 2018, 11:52pm 10

Jonathanw82:
I do however seem to be getting 4.6v at the relay signal terminal...

Because you have powered the Uno with 5volt on the V-in pin (wrong).
Leo..

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