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[[Image:7805_schematic.png | 300px ]]
Notice the regulator has three legs. Each of these legs has to be connected to the right thing. From page 2 of the datasheet for the regulator [http://www.fairchildsemi.com/ds/LM/LM7805.pdf datasheet], under "Pin Assignment" we see what each of the legs are. Looking at the front, they are numbered 1, 2, and 3, from left to right, and are labeled "Input", "GND", and "Output":
[[Image:7805_pinout.png | 200px]]
**what is the voltage across the input to the voltage regulator?
**what is the voltage across the output from the voltage regulator?
**how much current is flowing through the bulb? According to the datasheet for the bulb [http://www.jameco.com/Jameco/Products/ProdDS/210008.pdf datasheet] , how much current should the bulb draw? REMEMBER: measuring current with a multimeter is different than measuring voltage. You need to "break the circuit" and re-connect it through the multimeter.
=== Series and Parallel===