diodes ve direction only?

That is called an open circuit which is even cheaper than a diode. A diode let's -ve current flow one way and +ve current the opposite way, and neither the other. -ve one way & +ve the other means exactly the same thing. To block one and not the other requires a quantum membrane, but that is of no use in an electical circuit. The diode pic with antonic's circle is electrically exactly the same as the one below it with -ve flowing from left to right. So if the -ve flowing from left to right is acceptable, why isn't the one he circled? YET AGAIN, give and example or a description or a circuit/sketch of what is to be done. Or try a diode in the circuit application and THEN tell me it does NOT work.

jstruckman wrote: I diode will not do that. Antonic wants negative to go one direction, and no -ve and no +ve to come back through. A diode will still allow +ve to come back through. That is why he has the red circle on the diode showing +ve still coming back through.

Spot on. I was tapping into the side folding mirrors with another switch so I couldn't allow +ve to flow back into my circuit. I've now found another way to do this... Thanks all!

Pray tell, how? A diode will do it. Unless you mean you needed two diodes - ie, one for your tap plus one inserted into the existing feed. It can be done with a relay, but diodes are usually used instead for simplicity. And as I said, why did you only circle ONE of those diagrams when the one under it is exactly the same? (But deals with -ve flow.) And people wonder why I tell them only to worry about conventional current flow and not worry about electron or ion flow. It's ok once you master the basics, tho even then I have seen experienced experts get confused - viz the text book author that wanted to know if "electricity" was the flow (sic) of +ve charge OR -ve (electron) charge where OR meant else implied one OR the other but not both. Poor fool.

FYI - I referred to this thread in another reply so if you can justify your actions or reasoning... (That's for both antonic & jstruckman. I'm referring especially to antonic's last reply above.)