Problem with 5v power supply

Try redrawing your circuit:

• The 0V rail (negative side of input and output voltages) should run horizontally only, all the way along the bottom of the diagram;
• The regulator should have its input on the left and its output on the right;
• Positive voltages should be higher up in the diagram than the 0V rail;
• Input voltage should be shown;
• Part number for the regulator should be shown.
  
• All text should be horizontal and read from left to right.

Once you've done that, the problem should become clear to you. If it doesn't, repost it here.

 

Are you sure the input voltage is 12V?

Are you sure the LED's series resistor is 100Ω?

Assuming the LED's forward voltage is about 2V the LED current will be about 30 mA. This will cause the regultor to dissipate about 0.2W (if the input voltage really is 12V) which will make it detectably warm but not noticeably warm with that heatsink on it.

 

Brown black black is 10Ω

 

You may have damaged the LED too. 300 mA is probably too much.

 

Ho ho ho! Like the little Christmas tree lights? Must be a pretty good LED if it somehow goes into thermal shutdown at 300 mA and then lights up again after it cools off. Oh, wait, you were kidding us about the "blinking," riiiight?

This must be the time of year to replace LEDs. Working late into the evening, I burned out two of them on the same day this week, one because I read the color-code wrong on a 1/4 watt current-limiting resistor, another when I accidentally shorted two wires together on the breadboard, probably connecting the LED directly across the power supply rails. The 12 V 1.5 A voltage-regulated power supply didn't even hiccup, but the resistor was toast, as were the two LEDs.

Good thing they were just two out of a hundred or so I purchased for about five bucks (late in the last century) from Mendelson Electronics, a surplus store here in Dayton. Lessons re-learned: (1) wear the magic magnifying 2X four-diopter OptiVISOR and (2) use spaghetti insulation over those pesky long leads of the resistors and capacitors until they are transferred from the breadboard to a circuit board. <sigh> This was so much easier twenty years ago. Plus, I was allowed to ride my motorcycle then.

 

That depends on what kind of a load you plan on using. Or did you just want to light up the LED (which I presume it does now)?