10 years ago
It will light up shortely and then die forever.
If you don' tconnect a current limiting resistor in series with the LED, you will get smashed in the face by high pressure water.
What would happen if you put your face right in front of a fire-hydrant and turned it on to get a drink? Attach the same water supply to a drinking fountain and you'd do much better. The drinking fountain limits the flow of water. Put a 180R resistor in series with the LED and harmony will be restored.
When I had the bright idea to attach a 1.5v to a 9v battery (who knows why...), it lit very brightly for about a second, then it burned out.
It will "burn" brightly, for a while, then it won't (at all). Take the advice of Jack':http://led.linear1.org/1led.wiz L
Without the use of a current limiting resistor, you will bring dishonor upon your family.
The magical blue smoke will escape.
It would shatter. In my workshop a 9v battery brushed against a 1.5v led and the thing exploded. Plastic shards everywhere. My recommendation: don't do it.
Without a current limiting resistor the power supply will be damaged by the burning LED/