So in my case:
When not attached to the bridge, E+ to E- is 5V: E+=5V and E-=0V
When attached to the bridge, E+ to E- is 0V: Both 5V
So in my case:
When not attached to the bridge, E+ to E- is 5V: E+=5V and E-=0V
When attached to the bridge, E+ to E- is 0V: Both 5V