dispensers stay powered after activation when the redstone line for activation is beside it
place a dispenser with a repeater behind it.
add a redstone line from the repeater that goes on a block next to the dispenser.
power the redstone line.
the dispenser will stay triggered and the redstone powered.
First video, the dispenser is irrelevant, as replacing the dispenser with any other block provides the same result. The second video is MC-108, the dispenser stays powered because it's bud-powered.
[media]