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Author Topic: Relay and LCD Issue  (Read 1973 times)
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Left Coast, CA (USA)
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[/quoLefty, what do you mean by "CAP to true Ground"?
te]

To the negative side of the external power supply you are using to power the relay coils.

Lefty
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The data sheets unfortunate choice of label for ULN pin 9 seems to be causing confusion.
Pin 9 is where all the diode anodes are connected together... thus the label 'diode common'.

Pin 9 should be connected to +5 volts of the relay board, not to ground.
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I have wired the pin 9 to +5 and pin 8 to GND. Is that correct?
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