I'm using a 12V power supply for powering my Arduino Uno board. I want to make a lamp blink that's apparently rated for up to 125 V (it lights enough under 12 V, but it's way too dim under the standard 5 V). Since the board's output pins' HIGH value is 5 V regardless of the power supply, I figured I'd use a 2N222 transistor as a switch to switch the 12 V to the lamp.
So I have the collector connected to the Vin pin, the emitter pin connected to the lamp, and the base pin attached to a 10K ohm resistor and then one of the output pins.
The problem is whenever the output pin is HIGH, the voltage read across the collector/emitter is still 5 V (a little less actually). Why is this? I figured the transistor would act as a simple switch and turn on the 12 V across it...?