World's most basic button circuit question.

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Hi,

Ugh. I don't understand what I am doing wrong.

I've attached a picture of the circuit in iCircuit (which works) but when I put everything on the Arduino (UNO) it doesn't work the way I expect.

I have 5V going through a 330 Ohm resister that goes into a lead of a push button. The other lead of the button goes into the + lead of an LED. The - lead of the LED goes directly into GND on the Arduino.

I expect the LED to be off by default and on when I push the button. But the LED is on all the time. (???)

I suspect that the problem is how you wired to the switch terminals. A lot of those small 'buttons' have four terminals but you must be sure you are not using two adjacent terminals that are direct connections to each other rather then switched to the other pair of contacts. This is why having a digital multimeter is so important to anyone starting off to learn to build electronic circuits. Using the ohm meter function of a multmeter can confirm that you understand which terminals will actually open and close a circuit as you manipulate the switch button. Anyway that's my best guess at the source of your problem.
Lefty

I am totally new to electronics and I'm obviously doing something wrong.

Any advice would be much appreciated.

Thanks,
LT