I would think the power dissapears when the input it gone but does not
Steps to Reproduce:
1. Place redstone torch down
2. redstone dust full length until no more power
3. place a repeater at a 90 degree angle
4. Then redstone dust after repeater back into the circuit does not matter left or right
5. then on the original dust continue it till it has no power
6. repeat steps 3 and 4
7. then extend the original dust again
8. Go back and break the fist repeater. the line should go out but it stay on?