Switch open only with power

[David Turner]

I'm trying to find a specific type of switch. Once I have power going to a pcb I want the switch to remain off until I switch it on and then stay on after I switch it on. Here's what I'm having a hard time finding. I'm trying to find one that will automatically switch off as soon as the power is turned off. I hope that makes sense. Has anyone heard about a switch like that?

 

[ronsimpson]

There probably is a switch like that but I can't find it.
You can make one.
Here is a push button, normally open switch, and relay.
When power is applied both the switch and relay are open, no power to the load.
Push the button for a short amount of time and power goes to the load and the relay coil.
The relay sends power to the load and keeps doing that.
The relay is reset by dropping the power in. (below 1/2 voltage)